From 88c502146c211a991649f71f3952965997d8b49d Mon Sep 17 00:00:00 2001
From: Thomas Koenig <tkoenig@gcc.gnu.org>
Date: Tue, 6 Jun 2017 22:23:07 +0000
Subject: [PATCH] backport: re PR fortran/80975 (matmul for zero-length arrays)

2017-06-06  Thomas Koenig  <tkoenig@gcc.gnu.org>

	Backport from trunk
	PR fortran/80975
	* m4/matmul_internal.m4:  Move zeroing before early return.
	* generated/matmul_c10.c: Regenerated.
	* generated/matmul_c16.c: Regenerated.
	* generated/matmul_c4.c: Regenerated.
	* generated/matmul_c8.c: Regenerated.
	* generated/matmul_i1.c: Regenerated.
	* generated/matmul_i16.c: Regenerated.
	* generated/matmul_i2.c: Regenerated.
	* generated/matmul_i4.c: Regenerated.
	* generated/matmul_i8.c: Regenerated.
	* generated/matmul_r10.c: Regenerated.
	* generated/matmul_r16.c: Regenerated.
	* generated/matmul_r4.c: Regenerated.
	* generated/matmul_r8.c: Regenerated.

2017-06-06  Thomas Koenig  <tkoenig@gcc.gnu.org>

	Backport from trunk
	PR fortran/80975
	* gfortran.dg/matmul_16.f90: New test.
	* gfortran.dg/inline_matmul_18.f90: New test.

From-SVN: r248935
---
 gcc/testsuite/ChangeLog                       |  7 ++++
 .../gfortran.dg/inline_matmul_18.f90          | 16 ++++++++
 gcc/testsuite/gfortran.dg/matmul_16.f90       | 13 ++++++
 libgfortran/ChangeLog                         | 19 +++++++++
 libgfortran/Makefile.in                       |  5 ++-
 libgfortran/generated/matmul_c10.c            | 40 +++++++++----------
 libgfortran/generated/matmul_c16.c            | 40 +++++++++----------
 libgfortran/generated/matmul_c4.c             | 40 +++++++++----------
 libgfortran/generated/matmul_c8.c             | 40 +++++++++----------
 libgfortran/generated/matmul_i1.c             | 40 +++++++++----------
 libgfortran/generated/matmul_i16.c            | 40 +++++++++----------
 libgfortran/generated/matmul_i2.c             | 40 +++++++++----------
 libgfortran/generated/matmul_i4.c             | 40 +++++++++----------
 libgfortran/generated/matmul_i8.c             | 40 +++++++++----------
 libgfortran/generated/matmul_r10.c            | 40 +++++++++----------
 libgfortran/generated/matmul_r16.c            | 40 +++++++++----------
 libgfortran/generated/matmul_r4.c             | 40 +++++++++----------
 libgfortran/generated/matmul_r8.c             | 40 +++++++++----------
 libgfortran/m4/matmul_internal.m4             |  8 ++--
 19 files changed, 322 insertions(+), 266 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/inline_matmul_18.f90
 create mode 100644 gcc/testsuite/gfortran.dg/matmul_16.f90

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 11c3c07036e..d9ed325a884 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2017-06-06  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	Backport from trunk
+	PR fortran/80975
+	* gfortran.dg/matmul_16.f90: New test.
+	* gfortran.dg/inline_matmul_18.f90: New test.
+
 2017-06-06  David S. Miller  <davem@davemloft.net>
 
 	* gcc.target/sparc/sparc-ret-3.c: New test.
diff --git a/gcc/testsuite/gfortran.dg/inline_matmul_18.f90 b/gcc/testsuite/gfortran.dg/inline_matmul_18.f90
new file mode 100644
index 00000000000..c846733c8c2
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/inline_matmul_18.f90
@@ -0,0 +1,16 @@
+! { dg-do  run }
+! { dg-options "-O -finline-matmul-limit=100 -fdump-tree-optimized" }
+! PR 80975 - this did not zero the result array in the library version;
+! make sure this also doesn't happen in the inline version.
+program bogus_matmul
+  implicit none
+  real :: M(3,0), v(0), w(3)
+
+  w = 7
+  w = matmul(M,v)
+  if( any(w .ne. 0) ) then
+    call abort
+  end if
+end program bogus_matmul
+! { dg-final { scan-tree-dump-times "matmul_r4" 0 "optimized" } }
+
diff --git a/gcc/testsuite/gfortran.dg/matmul_16.f90 b/gcc/testsuite/gfortran.dg/matmul_16.f90
new file mode 100644
index 00000000000..9def1336344
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/matmul_16.f90
@@ -0,0 +1,13 @@
+! { dg-do  run }
+! { dg-options "-finline-matmul-limit=0" }
+! PR 80975 - this did not zero the result array
+program bogus_matmul
+  implicit none
+  real :: M(3,0), v(0), w(3)
+
+  w = 7
+  w = matmul(M,v)
+  if( any(w .ne. 0) ) then
+    call abort
+  end if
+end program bogus_matmul
diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index e037f03f89a..ca109865be3 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,22 @@
+2017-06-06  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	Backport from trunk
+	PR fortran/80975
+	* m4/matmul_internal.m4:  Move zeroing before early return.
+	* generated/matmul_c10.c: Regenerated.
+	* generated/matmul_c16.c: Regenerated.
+	* generated/matmul_c4.c: Regenerated.
+	* generated/matmul_c8.c: Regenerated.
+	* generated/matmul_i1.c: Regenerated.
+	* generated/matmul_i16.c: Regenerated.
+	* generated/matmul_i2.c: Regenerated.
+	* generated/matmul_i4.c: Regenerated.
+	* generated/matmul_i8.c: Regenerated.
+	* generated/matmul_r10.c: Regenerated.
+	* generated/matmul_r16.c: Regenerated.
+	* generated/matmul_r4.c: Regenerated.
+	* generated/matmul_r8.c: Regenerated.
+
 2017-05-23  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	Backport from trunk
diff --git a/libgfortran/Makefile.in b/libgfortran/Makefile.in
index 05b183dcadb..4914a6f323f 100644
--- a/libgfortran/Makefile.in
+++ b/libgfortran/Makefile.in
@@ -137,8 +137,9 @@ am__aclocal_m4_deps = $(top_srcdir)/../config/depstand.m4 \
 	$(top_srcdir)/../ltversion.m4 $(top_srcdir)/../lt~obsolete.m4 \
 	$(top_srcdir)/acinclude.m4 $(top_srcdir)/../config/acx.m4 \
 	$(top_srcdir)/../config/no-executables.m4 \
-	$(top_srcdir)/../config/math.m4 $(top_srcdir)/../libtool.m4 \
-	$(top_srcdir)/configure.ac
+	$(top_srcdir)/../config/math.m4 \
+	$(top_srcdir)/../config/ax_check_define.m4 \
+	$(top_srcdir)/../libtool.m4 $(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
 am__CONFIG_DISTCLEAN_FILES = config.status config.cache config.log \
diff --git a/libgfortran/generated/matmul_c10.c b/libgfortran/generated/matmul_c10.c
index c8e7a6c37fb..d8b26c51374 100644
--- a/libgfortran/generated/matmul_c10.c
+++ b/libgfortran/generated/matmul_c10.c
@@ -307,15 +307,15 @@ matmul_c10_avx (gfc_array_c10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_c10_avx2 (gfc_array_c10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_c10_avx512f (gfc_array_c10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_c10_vanilla (gfc_array_c10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_c10 (gfc_array_c10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_c16.c b/libgfortran/generated/matmul_c16.c
index adbf1c81a7a..bc37fcd7139 100644
--- a/libgfortran/generated/matmul_c16.c
+++ b/libgfortran/generated/matmul_c16.c
@@ -307,15 +307,15 @@ matmul_c16_avx (gfc_array_c16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_c16_avx2 (gfc_array_c16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_c16_avx512f (gfc_array_c16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_c16_vanilla (gfc_array_c16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_c16 (gfc_array_c16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_c4.c b/libgfortran/generated/matmul_c4.c
index ff0e76a9275..683df98edca 100644
--- a/libgfortran/generated/matmul_c4.c
+++ b/libgfortran/generated/matmul_c4.c
@@ -307,15 +307,15 @@ matmul_c4_avx (gfc_array_c4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_c4_avx2 (gfc_array_c4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_c4_avx512f (gfc_array_c4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_c4_vanilla (gfc_array_c4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_c4 (gfc_array_c4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_c8.c b/libgfortran/generated/matmul_c8.c
index 483ebf114d7..9cf7623948b 100644
--- a/libgfortran/generated/matmul_c8.c
+++ b/libgfortran/generated/matmul_c8.c
@@ -307,15 +307,15 @@ matmul_c8_avx (gfc_array_c8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_c8_avx2 (gfc_array_c8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_c8_avx512f (gfc_array_c8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_c8_vanilla (gfc_array_c8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_c8 (gfc_array_c8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_COMPLEX_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_i1.c b/libgfortran/generated/matmul_i1.c
index 51cfcc05360..e2fd404d6a9 100644
--- a/libgfortran/generated/matmul_i1.c
+++ b/libgfortran/generated/matmul_i1.c
@@ -307,15 +307,15 @@ matmul_i1_avx (gfc_array_i1 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_1)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_i1_avx2 (gfc_array_i1 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_1)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_i1_avx512f (gfc_array_i1 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_1)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_i1_vanilla (gfc_array_i1 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_1)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_i1 (gfc_array_i1 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_1)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_i16.c b/libgfortran/generated/matmul_i16.c
index 90a422f4290..1601e104402 100644
--- a/libgfortran/generated/matmul_i16.c
+++ b/libgfortran/generated/matmul_i16.c
@@ -307,15 +307,15 @@ matmul_i16_avx (gfc_array_i16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_i16_avx2 (gfc_array_i16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_i16_avx512f (gfc_array_i16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_i16_vanilla (gfc_array_i16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_i16 (gfc_array_i16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_i2.c b/libgfortran/generated/matmul_i2.c
index 58be84fc9c8..c9b67af0aeb 100644
--- a/libgfortran/generated/matmul_i2.c
+++ b/libgfortran/generated/matmul_i2.c
@@ -307,15 +307,15 @@ matmul_i2_avx (gfc_array_i2 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_2)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_i2_avx2 (gfc_array_i2 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_2)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_i2_avx512f (gfc_array_i2 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_2)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_i2_vanilla (gfc_array_i2 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_2)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_i2 (gfc_array_i2 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_2)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_i4.c b/libgfortran/generated/matmul_i4.c
index 1e724d54ffa..47b061cc1d5 100644
--- a/libgfortran/generated/matmul_i4.c
+++ b/libgfortran/generated/matmul_i4.c
@@ -307,15 +307,15 @@ matmul_i4_avx (gfc_array_i4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_i4_avx2 (gfc_array_i4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_i4_avx512f (gfc_array_i4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_i4_vanilla (gfc_array_i4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_i4 (gfc_array_i4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_i8.c b/libgfortran/generated/matmul_i8.c
index f5ed84fa288..716ef13f5da 100644
--- a/libgfortran/generated/matmul_i8.c
+++ b/libgfortran/generated/matmul_i8.c
@@ -307,15 +307,15 @@ matmul_i8_avx (gfc_array_i8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_i8_avx2 (gfc_array_i8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_i8_avx512f (gfc_array_i8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_i8_vanilla (gfc_array_i8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_i8 (gfc_array_i8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_INTEGER_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_r10.c b/libgfortran/generated/matmul_r10.c
index 8f76faceabf..e0246b0f49b 100644
--- a/libgfortran/generated/matmul_r10.c
+++ b/libgfortran/generated/matmul_r10.c
@@ -307,15 +307,15 @@ matmul_r10_avx (gfc_array_r10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_r10_avx2 (gfc_array_r10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_r10_avx512f (gfc_array_r10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_r10_vanilla (gfc_array_r10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_r10 (gfc_array_r10 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_10)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_r16.c b/libgfortran/generated/matmul_r16.c
index 6a7687fdc33..7d34e2b5814 100644
--- a/libgfortran/generated/matmul_r16.c
+++ b/libgfortran/generated/matmul_r16.c
@@ -307,15 +307,15 @@ matmul_r16_avx (gfc_array_r16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_r16_avx2 (gfc_array_r16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_r16_avx512f (gfc_array_r16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_r16_vanilla (gfc_array_r16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_r16 (gfc_array_r16 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_16)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_r4.c b/libgfortran/generated/matmul_r4.c
index dbb31b05c3b..f6f86a6516f 100644
--- a/libgfortran/generated/matmul_r4.c
+++ b/libgfortran/generated/matmul_r4.c
@@ -307,15 +307,15 @@ matmul_r4_avx (gfc_array_r4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_r4_avx2 (gfc_array_r4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_r4_avx512f (gfc_array_r4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_r4_vanilla (gfc_array_r4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_r4 (gfc_array_r4 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_4)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/generated/matmul_r8.c b/libgfortran/generated/matmul_r8.c
index 23efed22e2a..9210d91718a 100644
--- a/libgfortran/generated/matmul_r8.c
+++ b/libgfortran/generated/matmul_r8.c
@@ -307,15 +307,15 @@ matmul_r8_avx (gfc_array_r8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -850,15 +850,15 @@ matmul_r8_avx2 (gfc_array_r8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1393,15 +1393,15 @@ matmul_r8_avx512f (gfc_array_r8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -1932,15 +1932,15 @@ matmul_r8_vanilla (gfc_array_r8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
@@ -2529,15 +2529,15 @@ matmul_r8 (gfc_array_r8 * const restrict retarray,
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = (GFC_REAL_8)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)
diff --git a/libgfortran/m4/matmul_internal.m4 b/libgfortran/m4/matmul_internal.m4
index d35968b3be5..f7b82483cd9 100644
--- a/libgfortran/m4/matmul_internal.m4
+++ b/libgfortran/m4/matmul_internal.m4
@@ -223,15 +223,15 @@ sinclude(`matmul_asm_'rtype_code`.m4')dnl
       b_offset = 1 + b_dim1;
       b -= b_offset;
 
-      /* Early exit if possible */
-      if (m == 0 || n == 0 || k == 0)
-	return;
-
       /* Empty c first.  */
       for (j=1; j<=n; j++)
 	for (i=1; i<=m; i++)
 	  c[i + j * c_dim1] = ('rtype_name`)0;
 
+      /* Early exit if possible */
+      if (m == 0 || n == 0 || k == 0)
+	return;
+
       /* Start turning the crank. */
       i1 = n;
       for (jj = 1; jj <= i1; jj += 512)