From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 20 Sep 2024 07:14:29 +0000 (+0200)
Subject: i386: Fix up _mm_min_ss etc. handling of zeros and NaNs [PR116738]
X-Git-Tag: releases/gcc-12.5.0~114
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f44314ec26af041cf9e5c794ba341435cc1b7c62;p=thirdparty%2Fgcc.git

i386: Fix up _mm_min_ss etc. handling of zeros and NaNs [PR116738]

min/max patterns for intrinsics which on x86 result in the second
input operand if the two operands are both zeros or one or both of them
are a NaN shouldn't use SMIN/SMAX RTL, because that is similarly to
MIN_EXPR/MAX_EXPR undefined what will be the result in those cases.

The following patch adds an expander which uses either a new pattern with
UNSPEC_IEEE_M{AX,IN} or use the S{MIN,MAX} representation of the same.

2024-09-20  Uros Bizjak  <ubizjak@gmail.com>
	    Jakub Jelinek  <jakub@redhat.com>

	PR target/116738
	* config/i386/subst.md (mask_scalar_operand_arg34,
	mask_scalar_expand_op3, round_saeonly_scalar_mask_arg3): New
	subst attributes.
	* config/i386/sse.md
	(<sse>_vm<code><mode>3<mask_scalar_name><round_saeonly_scalar_name>):
	Change from define_insn to define_expand, rename the old define_insn
	to ...
	(*<sse>_vm<code><mode>3<mask_scalar_name><round_saeonly_scalar_name>):
	... this.
	(<sse>_ieee_vm<ieee_maxmin><mode>3<mask_scalar_name><round_saeonly_scalar_name>):
	New define_insn.

	* gcc.target/i386/sse-pr116738.c: New test.

(cherry picked from commit 624d3af025e820ede7ec4334f7a2d5d4731c99a9)
---

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 09b308e03c7..d65ad5f1736 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -2866,7 +2866,27 @@
 	   (const_string "*")))
    (set_attr "mode" "<ssescalarmode>")])
 
-(define_insn "<sse>_vm<code><mode>3<mask_scalar_name><round_saeonly_scalar_name>"
+(define_expand "<sse>_vm<code><mode>3<mask_scalar_name><round_saeonly_scalar_name>"
+  [(set (match_operand:VFH_128 0 "register_operand")
+	(vec_merge:VFH_128
+	  (smaxmin:VFH_128
+	    (match_operand:VFH_128 1 "register_operand")
+	    (match_operand:VFH_128 2 "nonimmediate_operand"))
+	 (match_dup 1)
+	 (const_int 1)))]
+  "TARGET_SSE"
+{
+  if (!flag_finite_math_only || flag_signed_zeros)
+    {
+      emit_insn (gen_<sse>_ieee_vm<maxmin_float><mode>3<mask_scalar_name><round_saeonly_scalar_name>
+		 (operands[0], operands[1], operands[2]
+		  <mask_scalar_operand_arg34>
+		  <round_saeonly_scalar_mask_arg3>));
+      DONE;
+    }
+})
+
+(define_insn "*<sse>_vm<code><mode>3<mask_scalar_name><round_saeonly_scalar_name>"
   [(set (match_operand:VFH_128 0 "register_operand" "=x,v")
 	(vec_merge:VFH_128
 	  (smaxmin:VFH_128
@@ -2884,6 +2904,25 @@
    (set_attr "prefix" "<round_saeonly_scalar_prefix>")
    (set_attr "mode" "<ssescalarmode>")])
 
+(define_insn "<sse>_ieee_vm<ieee_maxmin><mode>3<mask_scalar_name><round_saeonly_scalar_name>"
+  [(set (match_operand:VFH_128 0 "register_operand" "=x,v")
+	(vec_merge:VFH_128
+	  (unspec:VFH_128
+	    [(match_operand:VFH_128 1 "register_operand" "0,v")
+	     (match_operand:VFH_128 2 "nonimmediate_operand" "xm,<round_saeonly_scalar_constraint>")]
+	    IEEE_MAXMIN)
+	 (match_dup 1)
+	 (const_int 1)))]
+  "TARGET_SSE"
+  "@
+   <ieee_maxmin><ssescalarmodesuffix>\t{%2, %0|%0, %<iptr>2}
+   v<ieee_maxmin><ssescalarmodesuffix>\t{<round_saeonly_scalar_mask_op3>%2, %1, %0<mask_scalar_operand3>|%0<mask_scalar_operand3>, %1, %<iptr>2<round_saeonly_scalar_mask_op3>}"
+  [(set_attr "isa" "noavx,avx")
+   (set_attr "type" "sse")
+   (set_attr "btver2_sse_attr" "maxmin")
+   (set_attr "prefix" "<round_saeonly_scalar_prefix>")
+   (set_attr "mode" "<ssescalarmode>")])
+
 (define_mode_attr addsub_cst [(V4DF "5") (V2DF "1")
                               (V4SF "5") (V8SF "85")])
 
diff --git a/gcc/config/i386/subst.md b/gcc/config/i386/subst.md
index bb86f82905f..6302097c53c 100644
--- a/gcc/config/i386/subst.md
+++ b/gcc/config/i386/subst.md
@@ -344,6 +344,8 @@
 (define_subst_attr "mask_scalarcz_operand4" "mask_scalarcz" "" "%{%5%}%N4")
 (define_subst_attr "mask_scalar4_dest_false_dep_for_glc_cond" "mask_scalar" "1" "operands[4] == CONST0_RTX(<MODE>mode)")
 (define_subst_attr "mask_scalarc_dest_false_dep_for_glc_cond" "mask_scalarc" "1" "operands[3] == CONST0_RTX(V8HFmode)")
+(define_subst_attr "mask_scalar_operand_arg34" "mask_scalar" "" ", operands[3], operands[4]")
+(define_subst_attr "mask_scalar_expand_op3" "mask_scalar" "3" "5")
 
 (define_subst "mask_scalar"
   [(set (match_operand:SUBST_V 0)
@@ -451,6 +453,7 @@
 (define_subst_attr "round_saeonly_scalar_constraint" "round_saeonly_scalar" "vm" "v")
 (define_subst_attr "round_saeonly_scalar_prefix" "round_saeonly_scalar" "vex" "evex")
 (define_subst_attr "round_saeonly_scalar_nimm_predicate" "round_saeonly_scalar" "nonimmediate_operand" "register_operand")
+(define_subst_attr "round_saeonly_scalar_mask_arg3" "round_saeonly_scalar" "" ", operands[<mask_scalar_expand_op3>]")
 
 (define_subst "round_saeonly_scalar"
   [(set (match_operand:SUBST_V 0)
diff --git a/gcc/testsuite/gcc.target/i386/sse-pr116738.c b/gcc/testsuite/gcc.target/i386/sse-pr116738.c
new file mode 100644
index 00000000000..5b31bf24748
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/sse-pr116738.c
@@ -0,0 +1,28 @@
+/* PR target/116738 */
+/* { dg-do run } */
+/* { dg-options "-O2 -msse" } */
+/* { dg-require-effective-target sse } */
+
+#include "sse-check.h"
+
+static inline float
+clamp (float f)
+{
+  __m128 v = _mm_set_ss (f);
+  __m128 zero = _mm_setzero_ps ();
+  __m128 greatest = _mm_set_ss (__FLT_MAX__);
+  v = _mm_min_ss (v, greatest);
+  v = _mm_max_ss (v, zero);
+  return _mm_cvtss_f32 (v);
+}
+
+static void
+sse_test (void)
+{
+  float f = clamp (-0.0f);
+  if (f != 0.0f || __builtin_signbitf (f))
+    abort ();
+  f = clamp (__builtin_nanf (""));
+  if (__builtin_isnanf (f) || f != __FLT_MAX__)
+    abort ();
+}