[gcc r12-8204] tree-optimization/105312 - fix ISEL VCOND expansion

[gcc r12-8204] tree-optimization/105312 - fix ISEL VCOND expansion

[Richard Biener]

https://gcc.gnu.org/g:36f1de95a61132f63c0c07ef154abd9f435721ac

commit r12-8204-g36f1de95a61132f63c0c07ef154abd9f435721ac
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Apr 20 10:17:24 2022 +0200

    tree-optimization/105312 - fix ISEL VCOND expansion
    
    The following aligns ISEL VEC_COND_EXPR expansion using VCOND
    with the optab query done by vector lowering.  Instead of only
    allowing the signed optab to provide EQ/NE compares we allow both
    here though since there seems to be no documented canonicalization.
    
    2022-04-20  Richard Biener  <rguenther@suse.de>
    
            PR tree-optimization/105312
            * gimple-isel.cc (gimple_expand_vec_cond_expr): Query both
            VCOND and VCONDU for EQ and NE.
    
            * gcc.target/arm/pr105312.c: New testcase.

Diff:
---
 gcc/gimple-isel.cc                      |  8 ++++++++
 gcc/testsuite/gcc.target/arm/pr105312.c | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/gcc/gimple-isel.cc b/gcc/gimple-isel.cc
index 3635585bf45..a8f7a0d25d0 100644
--- a/gcc/gimple-isel.cc
+++ b/gcc/gimple-isel.cc
@@ -245,6 +245,14 @@ gimple_expand_vec_cond_expr (struct function *fun, gimple_stmt_iterator *gsi,
 			GET_MODE_NUNITS (cmp_op_mode)));
 
   icode = get_vcond_icode (mode, cmp_op_mode, unsignedp);
+  /* Some targets do not have vcondeq and only vcond with NE/EQ
+     but not vcondu, so make sure to also try vcond here as
+     vcond_icode_p would canonicalize the optab query to.  */
+  if (icode == CODE_FOR_nothing
+      && (tcode == NE_EXPR || tcode == EQ_EXPR)
+      && ((icode = get_vcond_icode (mode, cmp_op_mode, !unsignedp))
+	  != CODE_FOR_nothing))
+    unsignedp = !unsignedp;
   if (icode == CODE_FOR_nothing)
     {
       if (tcode == LT_EXPR
diff --git a/gcc/testsuite/gcc.target/arm/pr105312.c b/gcc/testsuite/gcc.target/arm/pr105312.c
new file mode 100644
index 00000000000..a02831bcbcf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr105312.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_neon_ok } */
+/* { dg-options "-mcpu=cortex-a15" } */
+/* { dg-add-options arm_neon } */
+
+typedef float stress_matrix_type_t;
+typedef unsigned int size_t;
+static void __attribute__((optimize("-O3"))) stress_matrix_xy_identity(
+ const size_t n,
+ stress_matrix_type_t a[restrict n][n],
+ stress_matrix_type_t b[restrict n][n],
+ stress_matrix_type_t r[restrict n][n])
+{
+ register size_t i;
+ (void)a;
+ (void)b;
+ for (i = 0; i < n; i++) {
+  register size_t j;
+  for (j = 0; j < n; j++)
+   r[i][j] = (i == j) ? 1.0 : 0.0;
+   return;
+ }
+}