i386: Add V2SFmode DIV insn pattern [PR95046, PR103797]

Use V4SFmode "DIVPS X,Y" with [y0, y1, 1.0f, 1.0f] as a divisor
to avoid division by zero.

2021-12-24  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:

	PR target/95046
	PR target/103797
	* config/i386/mmx.md (divv2sf3): New instruction pattern.

gcc/testsuite/ChangeLog:

	PR target/95046
	PR target/103797
	* gcc.target/i386/pr95046-1.c (test_div): Add.
	(dg-options): Add -mno-recip.

diff --git a/gcc/config/i386/mmx.md b/gcc/config/i386/mmx.md
index 6c5cbcf..5a57556 100644 (file)
--- a/gcc/config/i386/mmx.md
+++ b/gcc/config/i386/mmx.md
@@ -523,6 +523,26 @@
    (set_attr "prefix" "*,orig,vex")
    (set_attr "mode" "V2SF,V4SF,V4SF")])
 
+(define_expand "divv2sf3"
+  [(set (match_operand:V2SF 0 "register_operand")
+       (div:V2SF (match_operand:V2SF 1 "register_operand")
+                 (match_operand:V2SF 2 "register_operand")))]
+  "TARGET_MMX_WITH_SSE"
+{
+  rtx op0 = lowpart_subreg (V4SFmode, operands[0],
+                           GET_MODE (operands[0]));
+  rtx op1 = lowpart_subreg (V4SFmode, operands[1],
+                           GET_MODE (operands[1]));
+  rtx op2 = gen_rtx_VEC_CONCAT (V4SFmode, operands[2],
+                               force_reg (V2SFmode, CONST1_RTX (V2SFmode)));
+  rtx tmp = gen_reg_rtx (V4SFmode);
+
+  emit_insn (gen_rtx_SET (tmp, op2));
+
+  emit_insn (gen_divv4sf3 (op0, op1, tmp));
+  DONE;
+})
+
 (define_expand "mmx_<code>v2sf3"
   [(set (match_operand:V2SF 0 "register_operand")
         (smaxmin:V2SF

diff --git a/gcc/testsuite/gcc.target/i386/pr95046-1.c b/gcc/testsuite/gcc.target/i386/pr95046-1.c
index bcc8bb5..2a0e6db 100644 (file)
--- a/gcc/testsuite/gcc.target/i386/pr95046-1.c
+++ b/gcc/testsuite/gcc.target/i386/pr95046-1.c
@@ -1,6 +1,6 @@
 /* PR target/95046 */
 /* { dg-do compile { target { ! ia32 } } } */
-/* { dg-options "-O3 -ffast-math -msse2" } */
+/* { dg-options "-O3 -ffast-math -msse2 -mno-recip" } */
 
 
 float r[2], a[2], b[2];
@@ -33,6 +33,15 @@ test_mult (void)
 /* { dg-final { scan-assembler "\tv?mulps" } } */
 
 void
+test_div (void)
+{
+  for (int i = 0; i < 2; i++)
+    r[i] = a[i] / b[i];
+}
+
+/* { dg-final { scan-assembler "\tv?divps" } } */
+
+void
 test_min (void)
 {
   for (int i = 0; i < 2; i++)