re PR target/38598 (MIPS extendsidi2 does not have a LO alternative)

gcc/
	PR target/38598
	* config/mips/mips.md (extendsidi2): Add an "l" alternative.
	Update commentary.

gcc/testsuite/
	PR target/38598
	* gcc.target/mips/madd-7.c: Remove -mlong32.
	* gcc.target/mips/msub-7.c: Likewise.

From-SVN: r171572

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2011-03-27  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	PR target/38598
+	* config/mips/mips.md (extendsidi2): Add an "l" alternative.
+	Update commentary.
+
 2011-03-27  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* config/mips/mips.c (mips_prepare_builtin_arg): Replace icode and

gcc/config/mips/mips.md

@@ -2963,19 +2963,25 @@
 ;; Extension insns.
 ;; Those for integer source operand are ordered widest source type first.
 
-;; When TARGET_64BIT, all SImode integer registers should already be in
+;; When TARGET_64BIT, all SImode integer and accumulator registers
-;; sign-extended form (see TRULY_NOOP_TRUNCATION and truncdisi2).  We can
+;; should already be in sign-extended form (see TRULY_NOOP_TRUNCATION
-;; therefore get rid of register->register instructions if we constrain
+;; and truncdisi2).  We can therefore get rid of register->register
-;; the source to be in the same register as the destination.
+;; instructions if we constrain the source to be in the same register as
+;; the destination.
 ;;
-;; The register alternative has type "arith" so that the pre-reload
+;; Only the pre-reload scheduler sees the type of the register alternatives;
-;; scheduler will treat it as a move.  This reflects what happens if
+;; we split them into nothing before the post-reload scheduler runs.
-;; the register alternative needs a reload.
+;; These alternatives therefore have type "move" in order to reflect
+;; what happens if the two pre-reload operands cannot be tied, and are
+;; instead allocated two separate GPRs.  We don't distinguish between
+;; the GPR and LO cases because we don't usually know during pre-reload
+;; scheduling whether an operand will be LO or not.
 (define_insn_and_split "extendsidi2"
-  [(set (match_operand:DI 0 "register_operand" "=d,d")
+  [(set (match_operand:DI 0 "register_operand" "=d,l,d")
-        (sign_extend:DI (match_operand:SI 1 "nonimmediate_operand" "0,m")))]
+        (sign_extend:DI (match_operand:SI 1 "nonimmediate_operand" "0,0,m")))]
   "TARGET_64BIT"
   "@
+   #
    #
    lw\t%0,%1"
   "&& reload_completed && register_operand (operands[1], VOIDmode)"
@@ -2984,7 +2990,7 @@
   emit_note (NOTE_INSN_DELETED);
   DONE;
 }
-  [(set_attr "move_type" "move,load")
+  [(set_attr "move_type" "move,move,load")
    (set_attr "mode" "DI")])
 
 (define_expand "extend<SHORT:mode><GPR:mode>2"

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2011-03-27  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	PR target/38598
+	* gcc.target/mips/madd-7.c: Remove -mlong32.
+	* gcc.target/mips/msub-7.c: Likewise.
+
 2011-03-27  Ira Rosen  <ira.rosen@linaro.org>
 
 	* gcc.dg/vect/vect-outer-5.c: Reduce the distance between data

gcc/testsuite/gcc.target/mips/madd-7.c

@@ -1,5 +1,4 @@
-/* -mlong32 added because of PR target/38598.  */
+/* { dg-options "-O2 -march=5kc" } */
-/* { dg-options "-O2 -march=5kc -mlong32" } */
 /* { dg-final { scan-assembler-not "\tmul\t" } } */
 /* { dg-final { scan-assembler "\tmadd\t" } } */
 

gcc/testsuite/gcc.target/mips/msub-7.c

@@ -1,5 +1,4 @@
-/* -mlong32 added because of PR target/38598.  */
+/* { dg-options "-O2 -march=5kc" } */
-/* { dg-options "-O2 -march=5kc -mlong32" } */
 /* { dg-final { scan-assembler-not "\tmul\t" } } */
 /* { dg-final { scan-assembler "\tmsub\t" } } */