https://gcc.gnu.org/g:be966baa353dfcc20b76b5a5586ab2494bb0a735
commit r15-4327-gbe966baa353dfcc20b76b5a5586ab2494bb0a735
Author: Tamar Christina <tamar.christ...@arm.com>
Date: Mon Oct 14 14:00:25 2024 +0100
simplify-rtx: Fix incorrect folding of shift and AND [PR117012]
The optimization added in r15-1047-g7876cde25cbd2f is using the wrong
operaiton to check for uniform constant vectors.
The Author intended to check that all the lanes in the vector are the same
and
so used CONST_VECTOR_DUPLICATE_P. However this only checks that the vector
is created from a pattern duplication, but doesn't say how many pattern
alternatives make up the duplication. Normally would would need to check
this
separately or use const_vec_duplicate_p.
Without this the optimization incorrectly triggers.
gcc/ChangeLog:
PR rtl-optimization/117012
* simplify-rtx.cc (simplify_context::simplify_binary_operation_1):
Use
const_vec_duplicate_p instead of CONST_VECTOR_DUPLICATE_P.
gcc/testsuite/ChangeLog:
PR rtl-optimization/117012
* gcc.target/aarch64/pr117012.c: New test.
Diff:
---
gcc/simplify-rtx.cc | 4 ++--
gcc/testsuite/gcc.target/aarch64/pr117012.c | 16 ++++++++++++++++
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index dc0d192dd218..4d024ec523b1 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -4088,10 +4088,10 @@ simplify_context::simplify_binary_operation_1 (rtx_code
code,
if (VECTOR_MODE_P (mode) && GET_CODE (op0) == ASHIFTRT
&& (CONST_INT_P (XEXP (op0, 1))
|| (GET_CODE (XEXP (op0, 1)) == CONST_VECTOR
- && CONST_VECTOR_DUPLICATE_P (XEXP (op0, 1))
+ && const_vec_duplicate_p (XEXP (op0, 1))
&& CONST_INT_P (XVECEXP (XEXP (op0, 1), 0, 0))))
&& GET_CODE (op1) == CONST_VECTOR
- && CONST_VECTOR_DUPLICATE_P (op1)
+ && const_vec_duplicate_p (op1)
&& CONST_INT_P (XVECEXP (op1, 0, 0)))
{
unsigned HOST_WIDE_INT shift_count
diff --git a/gcc/testsuite/gcc.target/aarch64/pr117012.c
b/gcc/testsuite/gcc.target/aarch64/pr117012.c
new file mode 100644
index 000000000000..537c0fa566c6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr117012.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#define vector16 __attribute__((vector_size(16)))
+
+vector16 unsigned char
+g (vector16 unsigned char a)
+{
+ vector16 signed char b = (vector16 signed char)a;
+ b = b >> 7;
+ vector16 unsigned char c = (vector16 unsigned char)b;
+ vector16 unsigned char d = { 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0
};
+ return c & d;
+}
+
+/* { dg-final { scan-assembler-times {and\tv[0-9]+\.16b, v[0-9]+\.16b,
v[0-9]+\.16b} 1 } } */
