mips: msa: truncate immediate shift amount [PR101922]

When -mloongson-mmi is enabled, SHIFT_COUNT_TRUNCATED is turned off.
This causes untruncated immediate shift amount outputed into the asm,
and the GNU assembler refuses to assemble it.

Truncate immediate shift amount when outputing the asm instruction to
make GAS happy again.

gcc/

	PR target/101922
	* config/mips/mips-protos.h (mips_msa_output_shift_immediate):
	  Declare.
	* config/mips/mips.c (mips_msa_output_shift_immediate): New
	  function.
	* config/mips/mips-msa.md (vashl<mode>3, vashr<mode>3,
	  vlshr<mode>3): Call it.

gcc/testsuite/

	PR target/101922
	* gcc.target/mips/pr101922.c: New test.

gcc/config/mips/mips-msa.md

@@ -870,9 +870,12 @@
 	  (match_operand:IMSA 1 "register_operand" "f,f")
 	  (match_operand:IMSA 2 "reg_or_vector_same_uimm6_operand" "f,Uuv6")))]
   "ISA_HAS_MSA"
-  "@
-   srl.<msafmt>\t%w0,%w1,%w2
-   srli.<msafmt>\t%w0,%w1,%E2"
+{
+  if (which_alternative == 0)
+    return "srl.<msafmt>\t%w0,%w1,%w2";
+
+  return mips_msa_output_shift_immediate("srli.<msafmt>\t%w0,%w1,%E2", operands);
+}
   [(set_attr "type" "simd_shift")
    (set_attr "mode" "<MODE>")])
 
@@ -882,9 +885,12 @@
 	  (match_operand:IMSA 1 "register_operand" "f,f")
 	  (match_operand:IMSA 2 "reg_or_vector_same_uimm6_operand" "f,Uuv6")))]
   "ISA_HAS_MSA"
-  "@
-   sra.<msafmt>\t%w0,%w1,%w2
-   srai.<msafmt>\t%w0,%w1,%E2"
+{
+  if (which_alternative == 0)
+    return "sra.<msafmt>\t%w0,%w1,%w2";
+
+  return mips_msa_output_shift_immediate("srai.<msafmt>\t%w0,%w1,%E2", operands);
+}
   [(set_attr "type" "simd_shift")
    (set_attr "mode" "<MODE>")])
 
@@ -894,9 +900,12 @@
 	  (match_operand:IMSA 1 "register_operand" "f,f")
 	  (match_operand:IMSA 2 "reg_or_vector_same_uimm6_operand" "f,Uuv6")))]
   "ISA_HAS_MSA"
-  "@
-   sll.<msafmt>\t%w0,%w1,%w2
-   slli.<msafmt>\t%w0,%w1,%E2"
+{
+  if (which_alternative == 0)
+    return "sll.<msafmt>\t%w0,%w1,%w2";
+
+  return mips_msa_output_shift_immediate("slli.<msafmt>\t%w0,%w1,%E2", operands);
+}
   [(set_attr "type" "simd_shift")
    (set_attr "mode" "<MODE>")])
 

gcc/config/mips/mips-protos.h

@@ -317,6 +317,7 @@ extern const char *mips_output_sync_loop (rtx_insn *, rtx *);
 extern unsigned int mips_sync_loop_insns (rtx_insn *, rtx *);
 extern const char *mips_output_division (const char *, rtx *);
 extern const char *mips_msa_output_division (const char *, rtx *);
+extern const char *mips_msa_output_shift_immediate (const char *, rtx *);
 extern const char *mips_output_probe_stack_range (rtx, rtx);
 extern bool mips_hard_regno_rename_ok (unsigned int, unsigned int);
 extern bool mips_linked_madd_p (rtx_insn *, rtx_insn *);

gcc/config/mips/mips.c

@@ -14459,6 +14459,27 @@ mips_msa_output_division (const char *division, rtx *operands)
     }
   return s;
 }
+
+/* Return the assembly code for MSA immediate shift instructions,
+   which has the operands given by OPERANDS.  Truncate the shift amount
+   to make GAS happy.  */
+
+const char *
+mips_msa_output_shift_immediate (const char *shift, rtx *operands)
+{
+  rtx amount = operands[2];
+  machine_mode mode = amount->mode;
+
+  unsigned val = UINTVAL (CONST_VECTOR_ELT (amount, 0));
+  val &= GET_MODE_UNIT_BITSIZE (mode) - 1;
+  if (!val)
+    return "";
+
+  rtx c = gen_int_mode (val, GET_MODE_INNER (mode));
+  operands[2] = gen_const_vec_duplicate (mode, c);
+
+  return shift;
+}
 
 /* Return true if destination of IN_INSN is used as add source in
    OUT_INSN. Both IN_INSN and OUT_INSN are of type fmadd. Example:

gcc/testsuite/gcc.target/mips/pr101922.c

@@ -0,0 +1,19 @@
+/* PR target/101922
+   This was triggering an assembler error with -O3 -mmsa -mloongson-mmi. */
+
+/* { dg-do assemble } */
+/* { dg-options "-mmsa -mloongson-mmi" } */
+
+typedef __INT8_TYPE__ i8;
+typedef __INT32_TYPE__ i32;
+
+i8 d[16];
+
+i32 f(i32 x) {
+  int i;
+  for (i = 0; i < 16; i++) {
+    i32 t = (i32) d[i] >> 31;
+    x &= t;
+  }
+  return x;
+}