[gcc r14-9493] match.pd: Only merge truncation with conversion for -fno-signed-zeros

[gcc r14-9493] match.pd: Only merge truncation with conversion for -fno-signed-zeros

[Tamar Christina]

https://gcc.gnu.org/g:7dd3b2b09cbeb6712ec680a0445cb0ad41070423

commit r14-9493-g7dd3b2b09cbeb6712ec680a0445cb0ad41070423
Author: Joe Ramsay <Joe.Ramsay@arm.com>
Date:   Fri Mar 15 09:20:45 2024 +0000

    match.pd: Only merge truncation with conversion for -fno-signed-zeros
    
    This optimisation does not honour signed zeros, so should not be
    enabled except with -fno-signed-zeros.
    
    gcc/ChangeLog:
    
            * match.pd: Fix truncation pattern for -fno-signed-zeroes
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/aarch64/no_merge_trunc_signed_zero.c: New test.

Diff:
---
 gcc/match.pd                                       |  1 +
 .../aarch64/no_merge_trunc_signed_zero.c           | 24 ++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/gcc/match.pd b/gcc/match.pd
index 9ce313323a3..15a1e7350d4 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4858,6 +4858,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 (simplify
    (float (fix_trunc @0))
    (if (!flag_trapping_math
+	&& !HONOR_SIGNED_ZEROS (type)
 	&& types_match (type, TREE_TYPE (@0))
 	&& direct_internal_fn_supported_p (IFN_TRUNC, type,
 					  OPTIMIZE_FOR_BOTH))
diff --git a/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c b/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
new file mode 100644
index 00000000000..b2c93e55567
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-trapping-math -fsigned-zeros" } */
+
+#include <math.h>
+
+float
+f1 (float x)
+{
+  return (int) rintf(x);
+}
+
+double
+f2 (double x)
+{
+  return (long) rint(x);
+}
+
+/* { dg-final { scan-assembler "frintx\\ts\[0-9\]+, s\[0-9\]+" } } */
+/* { dg-final { scan-assembler "cvtzs\\ts\[0-9\]+, s\[0-9\]+" } } */
+/* { dg-final { scan-assembler "scvtf\\ts\[0-9\]+, s\[0-9\]+" } } */
+/* { dg-final { scan-assembler "frintx\\td\[0-9\]+, d\[0-9\]+" } } */
+/* { dg-final { scan-assembler "cvtzs\\td\[0-9\]+, d\[0-9\]+" } } */
+/* { dg-final { scan-assembler "scvtf\\td\[0-9\]+, d\[0-9\]+" } } */
+