[PATCH v2] match.pd: Change the MIN/MAX narrowing to MIN/MAX + convert

From 736b3afa2128386d961d651bb5599dfc96fabc60 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <[email protected]>
Date: Tue, 11 Aug 2026 12:39:54 +0800
Subject: [PATCH v2] match.pd: Change the MIN/MAX narrowing to MIN/MAX +
 convert

"(type) minmax ((wide_type) a, (wide_type) b) to minmax (a, b)" is limited
to the single use of the result. It doesn't support:

typedef int v2si __attribute__((vector_size (8)));
typedef long long v2di __attribute__((vector_size (16)));

v2si
func (v2si a, v2si b, v2di *p)
{
  v2di x = __builtin_convertvector (a, v2di);
  v2di y = __builtin_convertvector (b, v2di);
  v2di z = x < y ? x : y;
  *p = z;
  return __builtin_convertvector (z, v2si);
}

Change it to

minmax ((wide_type) a, (wide_type) b) -> (wide_type) minmax (a, b)

instead and update "for ocvt (convert float fix_trunc)" to replace
INTEGRAL_TYPE_P with ANY_INTEGRAL_TYPE_P to include vector int types
when supported by target, matching float conditionals which include
vector float types.  Now we generate

	pminsd	%xmm1, %xmm0
	pmovsxdq	%xmm0, %xmm1
	movaps	%xmm1, (%rdi)

instead of

	pmovsxdq	%xmm0, %xmm2
	pmovsxdq	%xmm1, %xmm1
	movdqa	%xmm2, %xmm0
	movdqa	%xmm2, %xmm3
	pcmpgtq	%xmm1, %xmm0
	pblendvb	%xmm0, %xmm1, %xmm3
	movdqa	%xmm3, %xmm0
	movaps	%xmm3, (%rdi)
	shufps	$232, %xmm3, %xmm0

gcc/

	PR middle-end/126784
	PR middle-end/126788
	* match.pd ((type) minmax ((wide_type) a, (wide_type) b)): Changed
	to ...
	(minmax ((wide_type) a, (wide_type) b)): This.
	(for ocvt (convert float fix_trunc)): Replace INTEGRAL_TYPE_P
	with ANY_INTEGRAL_TYPE_P and check if vector conversion is
	supported.

gcc/testsuite/

	PR middle-end/126784
	PR middle-end/126788
	* g++.dg/tree-ssa/vec-narrow-1.C: Use -msse4 and require int128
	for x86.
	* g++.dg/tree-ssa/vec-narrow-minmax-2.C: Likewise.
	* g++.target/i386/pr126784-1.C: New test.
	* g++.target/i386/pr126784-2.C: Likewise.
	* gcc.target/i386/pr126784-1.c: Likewise.
	* gcc.target/i386/pr126784-2.c: Likewise.
	* gcc.target/i386/pr126784-3.c: Likewise.
	* gcc.target/i386/pr126784-4.c: Likewise.
	* gcc.target/i386/pr126784-5.c: Likewise.
	* gcc.target/i386/pr126784-6.c: Likewise.
	* gcc.target/i386/pr126788-1.c: Likewise.

Signed-off-by: H.J. Lu <[email protected]>
---
 gcc/match.pd                                  | 38 ++++++++++---------
 gcc/testsuite/g++.dg/tree-ssa/vec-narrow-1.C  |  3 +-
 .../g++.dg/tree-ssa/vec-narrow-minmax-2.C     |  2 +
 gcc/testsuite/g++.target/i386/pr126784-1.C    | 26 +++++++++++++
 gcc/testsuite/g++.target/i386/pr126784-2.C    | 28 ++++++++++++++
 gcc/testsuite/gcc.target/i386/pr126784-1.c    | 24 ++++++++++++
 gcc/testsuite/gcc.target/i386/pr126784-2.c    | 27 +++++++++++++
 gcc/testsuite/gcc.target/i386/pr126784-3.c    | 11 ++++++
 gcc/testsuite/gcc.target/i386/pr126784-4.c    | 26 +++++++++++++
 gcc/testsuite/gcc.target/i386/pr126784-5.c    | 21 ++++++++++
 gcc/testsuite/gcc.target/i386/pr126784-6.c    | 25 ++++++++++++
 gcc/testsuite/gcc.target/i386/pr126788-1.c    | 22 +++++++++++
 12 files changed, 234 insertions(+), 19 deletions(-)
 create mode 100644 gcc/testsuite/g++.target/i386/pr126784-1.C
 create mode 100644 gcc/testsuite/g++.target/i386/pr126784-2.C
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126784-1.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126784-2.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126784-3.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126784-4.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126784-5.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126784-6.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126788-1.c

diff --git a/gcc/match.pd b/gcc/match.pd
index beea45357e2..0ec8636b60f 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4683,7 +4683,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	&& !TYPE_OVERFLOW_SANITIZED (type))
     (minus (minmax @0 @1) @2))))
 
-/* (type) minmax ((wide_type) a, (wide_type) b) -> minmax (a, b)
+/* minmax ((wide_type) a, (wide_type) b) -> (wide_type) minmax (a, b)
    when type matches the type of a and b, and wide_type is a wider
    type with the same signedness as type.  Extension is monotone, so it
    commutes with the comparison, and the truncation is then exact.  The
@@ -4693,18 +4693,15 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 (for minmax (min max)
      MINMAX (MIN_EXPR MAX_EXPR)
  (simplify
-  (convert (minmax:c@4 (convert@2 @0) (convert@3 @1)))
+  (minmax (convert @0) (convert @1))
   (if (ANY_INTEGRAL_TYPE_P (type)
-       && ANY_INTEGRAL_TYPE_P (TREE_TYPE (@2))
-       && types_match (type, TREE_TYPE (@0))
-       && types_match (type, TREE_TYPE (@1))
-       && types_match (TREE_TYPE (@2), TREE_TYPE (@3))
-       && element_precision (TREE_TYPE (@2)) > element_precision (type)
-       && TYPE_UNSIGNED (TREE_TYPE (@2)) == TYPE_UNSIGNED (type)
+       && ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
+       && types_match (TREE_TYPE (@0), TREE_TYPE (@1))
+       && element_precision (TREE_TYPE (@0)) < element_precision (type)
+       && TYPE_UNSIGNED (TREE_TYPE (@0)) == TYPE_UNSIGNED (type)
        && (!VECTOR_TYPE_P (type)
-	   || (single_use (@4)
-	       && target_supports_op_p (type, MINMAX, optab_vector))))
-   (minmax @0 @1))))
+	   || target_supports_op_p (TREE_TYPE (@0), MINMAX, optab_vector)))
+   (convert (minmax @0 @1)))))
 
 /* max (a, a + CST) -> a + CST where CST is positive.  */
 /* max (a, a + CST) -> a where CST is negative.  */
@@ -5816,19 +5813,19 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
     {
       tree inside_type = TREE_TYPE (@0);
       tree inter_type = TREE_TYPE (@1);
-      int inside_int = INTEGRAL_TYPE_P (inside_type);
+      int inside_int = ANY_INTEGRAL_TYPE_P (inside_type);
       int inside_ptr = POINTER_TYPE_P (inside_type);
       int inside_float = FLOAT_TYPE_P (inside_type);
       int inside_vec = VECTOR_TYPE_P (inside_type);
       unsigned int inside_prec = element_precision (inside_type);
       int inside_unsignedp = TYPE_UNSIGNED (inside_type);
-      int inter_int = INTEGRAL_TYPE_P (inter_type);
+      int inter_int = ANY_INTEGRAL_TYPE_P (inter_type);
       int inter_ptr = POINTER_TYPE_P (inter_type);
       int inter_float = FLOAT_TYPE_P (inter_type);
       int inter_vec = VECTOR_TYPE_P (inter_type);
       unsigned int inter_prec = element_precision (inter_type);
       int inter_unsignedp = TYPE_UNSIGNED (inter_type);
-      int final_int = INTEGRAL_TYPE_P (type);
+      int final_int = ANY_INTEGRAL_TYPE_P (type);
       int final_ptr = POINTER_TYPE_P (type);
       int final_float = FLOAT_TYPE_P (type);
       int final_vec = VECTOR_TYPE_P (type);
@@ -5856,7 +5853,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
     (if (((inter_int && inside_int) || (inter_float && inside_float))
 	 && (final_int || final_float)
 	 && inter_prec >= inside_prec
-	 && (inter_float || inter_unsignedp == inside_unsignedp))
+	 && (inter_float
+	     || ((!inter_vec
+		  || target_supports_op_p (TREE_TYPE (@0), ocvt, optab_vector))
+		 && inter_unsignedp == inside_unsignedp)))
      (ocvt @0))
 
     /* If we have a sign-extension of a zero-extended value, we can
@@ -5921,9 +5921,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
        represent it exactly and back to an integer, we can skip the
        floating-point conversion.  */
     (if (GIMPLE /* PR66211 */
-	 && inside_int && inter_float && final_int &&
-	 (unsigned) significand_size (TYPE_MODE (inter_type))
-	 >= inside_prec - !inside_unsignedp)
+	 && inside_int && inter_float && final_int
+	 && (!inside_vec
+	     || target_supports_op_p (TREE_TYPE (@0), ocvt, optab_vector))
+	 && (unsigned) significand_size (TYPE_MODE (inter_type))
+	    >= inside_prec - !inside_unsignedp)
      (convert @0)))))))
 
 /* (float_type)(integer_type) x -> trunc (x) if the type of x matches
diff --git a/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-1.C b/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-1.C
index cec5b0ba345..1f863b1d4a2 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-1.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-1.C
@@ -1,6 +1,7 @@
 // { dg-do compile }
 // { dg-options "-O2 -fdump-tree-optimized" }
-// { dg-additional-options "-mavx512vl -mavx512dq" { target { i?86-*-* x86_64-*-* } } }
+// { dg-additional-options "-msse4" { target { i?86-*-* x86_64-*-* } } }
+// { dg-require-effective-target int128 { target { i?86-*-* x86_64-*-* } } }
 // Extension is monotone, so it commutes with the comparison and the outer
 // truncation is exact.  The argument is lanewise, so a widened vector
 // MIN/MAX feeding a truncating conversion narrows.
diff --git a/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-minmax-2.C b/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-minmax-2.C
index d7fb7f06f16..7df25de0942 100644
--- a/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-minmax-2.C
+++ b/gcc/testsuite/g++.dg/tree-ssa/vec-narrow-minmax-2.C
@@ -1,5 +1,7 @@
 // { dg-do compile }
 // { dg-options "-O2 -fdump-tree-optimized" }
+// { dg-additional-options "-msse4" { target { i?86-*-* x86_64-*-* } } }
+// { dg-require-effective-target int128 { target { i?86-*-* x86_64-*-* } } }
 
 typedef int v2si __attribute__((vector_size (8)));
 typedef long long v2di __attribute__((vector_size (16)));
diff --git a/gcc/testsuite/g++.target/i386/pr126784-1.C b/gcc/testsuite/g++.target/i386/pr126784-1.C
new file mode 100644
index 00000000000..611d67ed37a
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr126784-1.C
@@ -0,0 +1,26 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2 -march=x86-64 -msse4 -std=c++17" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**_Z4funcDv2_iS_:
+**.LFB0:
+**	.cfi_startproc
+**	pminsd	%xmm1, %xmm0
+**	ret
+**	.cfi_endproc
+**...
+*/
+
+typedef int  v2si __attribute__((vector_size (8)));
+typedef long long v2di __attribute__((vector_size (16)));
+
+v2si
+func (v2si a, v2si b)
+{
+  v2di x = __builtin_convertvector (a, v2di);
+  v2di y = __builtin_convertvector (b, v2di);
+  v2di z = x < y ? x : y;
+  return __builtin_convertvector (z, v2si);
+}
diff --git a/gcc/testsuite/g++.target/i386/pr126784-2.C b/gcc/testsuite/g++.target/i386/pr126784-2.C
new file mode 100644
index 00000000000..3255b39b9a1
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr126784-2.C
@@ -0,0 +1,28 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2 -march=x86-64 -msse4 -std=c++17" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**_Z4funcDv2_iS_PDv2_x:
+**.LFB0:
+**	.cfi_startproc
+**	pminsd	%xmm1, %xmm0
+**	pmovsxdq	%xmm0, %xmm1
+**	movaps	%xmm1, \(%rdi\)
+**	ret
+**...
+*/
+
+typedef int  v2si __attribute__((vector_size (8)));
+typedef long long v2di __attribute__((vector_size (16)));
+
+v2si
+func (v2si a, v2si b, v2di *p)
+{
+  v2di x = __builtin_convertvector (a, v2di);
+  v2di y = __builtin_convertvector (b, v2di);
+  v2di z = x < y ? x : y;
+  *p = z;
+  return __builtin_convertvector (z, v2si);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126784-1.c b/gcc/testsuite/gcc.target/i386/pr126784-1.c
new file mode 100644
index 00000000000..73b581b0e7c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126784-1.c
@@ -0,0 +1,24 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**func:
+**.LFB0:
+**	.cfi_startproc
+**	cmpl	%esi, %edi
+**	movl	%esi, %eax
+**	cmovle	%edi, %eax
+**	ret
+**...
+*/
+
+int
+func (int a, int b)
+{
+  long long int x = a;
+  long long int y = b;
+  long long int z = x < y ? x : y;
+  return z;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126784-2.c b/gcc/testsuite/gcc.target/i386/pr126784-2.c
new file mode 100644
index 00000000000..f72495be5f9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126784-2.c
@@ -0,0 +1,27 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**func:
+**.LFB0:
+**	.cfi_startproc
+**	cmpl	%esi, %edi
+**	movl	%esi, %eax
+**	cmovle	%edi, %eax
+**	movslq	%eax, %rcx
+**	movq	%rcx, \(%rdx\)
+**	ret
+**...
+*/
+
+int
+func (int a, int b, long long int *p)
+{
+  long long int x = a;
+  long long int y = b;
+  long long int z = x < y ? x : y;
+  *p = z;
+  return z;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126784-3.c b/gcc/testsuite/gcc.target/i386/pr126784-3.c
new file mode 100644
index 00000000000..928140e64ee
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126784-3.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=x86-64" } */
+
+extern char *var1;
+extern int var2;
+
+void
+func (void)
+{
+  var2 = var1[1] + var1[0];
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126784-4.c b/gcc/testsuite/gcc.target/i386/pr126784-4.c
new file mode 100644
index 00000000000..e344480c3ba
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126784-4.c
@@ -0,0 +1,26 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2 -march=x86-64" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**func:
+**.LFB0:
+**	.cfi_startproc
+**	movdqa	.LC0\(%rip\), %xmm0
+**	movups	%xmm0, var\(%rip\)
+**	movdqa	.LC1\(%rip\), %xmm0
+**	movups	%xmm0, var\+16\(%rip\)
+**	ret
+**...
+*/
+
+extern unsigned int var[8];
+
+void
+func (void)
+{
+  int i;
+  for (i = 0; i < 8; i++)
+    var[i] = (float) i;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126784-5.c b/gcc/testsuite/gcc.target/i386/pr126784-5.c
new file mode 100644
index 00000000000..3b6a26e2e70
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126784-5.c
@@ -0,0 +1,21 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2 -march=x86-64" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**func:
+**.LFB0:
+**	.cfi_startproc
+**	movl	\$34, var\(%rip\)
+**	ret
+**...
+*/
+
+extern unsigned int var;
+
+void
+func (void)
+{
+  var = (float) 34;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126784-6.c b/gcc/testsuite/gcc.target/i386/pr126784-6.c
new file mode 100644
index 00000000000..403239039c0
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126784-6.c
@@ -0,0 +1,25 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2 -march=x86-64" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**func:
+**.LFB0:
+**	.cfi_startproc
+**	movl	%edi, %edi
+**	pxor	%xmm0, %xmm0
+**	cvtsi2ssq	%rdi, %xmm0
+**	cvttss2siq	%xmm0, %rax
+**	movl	%eax, var\(%rip\)
+**	ret
+**...
+*/
+
+extern unsigned int var;
+
+void
+func (unsigned int i)
+{
+  var = (float) i;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126788-1.c b/gcc/testsuite/gcc.target/i386/pr126788-1.c
new file mode 100644
index 00000000000..8a76b1045db
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126788-1.c
@@ -0,0 +1,22 @@
+/* { dg-do compile { target { *-*-linux* && { ! ia32 } } } } */
+/* { dg-options "-O2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc').  */
+/* { dg-final { check-function-bodies "**" "" "" { target "*-*-*" } {^\t?\.}  } } */
+
+/*
+**func:
+**.LFB0:
+**	.cfi_startproc
+**	ret
+**...
+*/
+
+typedef int  v2si __attribute__((vector_size (8)));
+typedef long long v2di __attribute__((vector_size (16)));
+
+v2si
+func (v2si a)
+{
+  v2di z = __builtin_convertvector (a, v2di);
+  return __builtin_convertvector (z, v2si);
+}
-- 
2.55.0