diff mbox series

[v2] match.pd: Only merge truncation with conversion for -fno-signed-zeros

Message ID 20240314092050.32508-1-Joe.Ramsay@arm.com
State New
Headers show
Series [v2] match.pd: Only merge truncation with conversion for -fno-signed-zeros | expand

Commit Message

Joe Ramsay March 14, 2024, 9:20 a.m. UTC 
This optimisation does not honour signed zeros, so should not be
enabled except with -fno-signed-zeros.

OK for master? I do not have commit rights for GCC, so if the patch
is fine would someone be able to commit for me? The bug is present
in all GCC versions from 12.1.0 onwards - is it possible to backport
this?

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Thanks,
Joe

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.
---
Changes from v1, whitespace change only.
 gcc/match.pd                                  |  1 +
 .../aarch64/no_merge_trunc_signed_zero.c      | 24 +++++++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/aarch64/no_merge_trunc_signed_zero.c
diff mbox series

Patch

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\[0-9\]+" } } */
+