[gcc r12-7276] Restrict the two sources of vect_recog_cond_expr_convert_pattern to be of the same type when convert

[gcc r12-7276] Restrict the two sources of vect_recog_cond_expr_convert_pattern to be of the same type when convert

[hongtao Liu]

https://gcc.gnu.org/g:754dce903ca28c4c2f2bc8614a8de5e631655f2e

commit r12-7276-g754dce903ca28c4c2f2bc8614a8de5e631655f2e
Author: liuhongt <hongtao.liu@intel.com>
Date:   Wed Feb 16 12:15:18 2022 +0800

    Restrict the two sources of vect_recog_cond_expr_convert_pattern to be of the same type when convert is extension.
    
    It's not equal to transform
    
     (cond (cmp @1 @2) (convert@3 @4) (convert@5 @6))
    
     to
    
     (convert (cmp @1 @2) (convert)@4 @6)
    
    when(convert@3 @4) is extension because it's zero_extend vs sign_extend.
    
    gcc/ChangeLog:
    
            PR tree-optimization/104551
            PR tree-optimization/103771
            * match.pd (cond_expr_convert_p): Add types_match check when
            convert is extension.
            * tree-vect-patterns.cc
            (gimple_cond_expr_convert_p): Adjust comments.
            (vect_recog_cond_expr_convert_pattern): Ditto.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/i386/pr104551.c: New test.

Diff:
---
 gcc/match.pd                             |  6 ++++++
 gcc/testsuite/gcc.target/i386/pr104551.c | 24 ++++++++++++++++++++++++
 gcc/tree-vect-patterns.cc                |  6 ++++--
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index 05a10ab6bfd..8b6f22f1065 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7698,5 +7698,11 @@ and,
 	  == TYPE_PRECISION (TREE_TYPE (@2))
        && TYPE_PRECISION (TREE_TYPE (@0))
 	  == TYPE_PRECISION (TREE_TYPE (@3))
+       /* For vect_recog_cond_expr_convert_pattern, @2 and @3 can differ in
+	  signess when convert is truncation, but not ok for extension since
+	  it's sign_extend vs zero_extend.  */
+       && (TYPE_PRECISION (TREE_TYPE (@0)) > TYPE_PRECISION (type)
+	   || (TYPE_UNSIGNED (TREE_TYPE (@2))
+	       == TYPE_UNSIGNED (TREE_TYPE (@3))))
        && single_use (@4)
        && single_use (@5))))
diff --git a/gcc/testsuite/gcc.target/i386/pr104551.c b/gcc/testsuite/gcc.target/i386/pr104551.c
new file mode 100644
index 00000000000..6300f25c0d5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr104551.c
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -mavx2" } */
+/* { dg-require-effective-target avx2 } */
+
+unsigned int
+__attribute__((noipa))
+test(unsigned int a, unsigned char p[16]) {
+  unsigned int res = 0;
+  for (unsigned b = 0; b < a; b += 1)
+    res = p[b] ? p[b] : (char) b;
+  return res;
+}
+
+int main ()
+{
+  unsigned int a = 16U;
+  unsigned char p[16];
+  for (int i = 0; i != 16; i++)
+    p[i] = (unsigned char)128;
+  unsigned int res = test (a, p);
+  if (res != 128)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
index a8f96d59643..217bdfd7045 100644
--- a/gcc/tree-vect-patterns.cc
+++ b/gcc/tree-vect-patterns.cc
@@ -929,8 +929,10 @@ vect_reassociating_reduction_p (vec_info *vinfo,
    with conditions:
    1) @1, @2, c, d, a, b are all integral type.
    2) There's single_use for both @1 and @2.
-   3) a, c and d have same precision.
+   3) a, c have same precision.
    4) c and @1 have different precision.
+   5) c, d are the same type or they can differ in sign when convert is
+   truncation.
 
    record a and c and d and @3.  */
 
@@ -952,7 +954,7 @@ extern bool gimple_cond_expr_convert_p (tree, tree*, tree (*)(tree));
    TYPE_PRECISION (TYPE_E) != TYPE_PRECISION (TYPE_CD);
    TYPE_PRECISION (TYPE_AB) == TYPE_PRECISION (TYPE_CD);
    single_use of op_true and op_false.
-   TYPE_AB could differ in sign.
+   TYPE_AB could differ in sign when (TYPE_E) A is a truncation.
 
    Input: