From: Andrew Pinski <apin...@marvell.com>
The problem here is the aarch64_expand_setmem code did not check
STRICT_ALIGNMENT if it is creating an overlapping store.
This patch adds that check and the testcase works.
gcc/ChangeLog:
PR target/101934
* config/aarch64/aarch64.c (aarch64_expand_setmem):
Check STRICT_ALIGNMENT before creating an overlapping
store.
gcc/testsuite/ChangeLog:
PR target/101934
* gcc.target/aarch64/memset-strict-align-1.c: New test.
---
gcc/config/aarch64/aarch64.c | 4 +--
.../aarch64/memset-strict-align-1.c | 28 +++++++++++++++++++
2 files changed, 30 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/memset-strict-align-1.c
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 3213585a588..26d59ba1e13 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -23566,8 +23566,8 @@ aarch64_expand_setmem (rtx *operands)
/* Do certain trailing copies as overlapping if it's going to be
cheaper. i.e. less instructions to do so. For instance doing a 15
byte copy it's more efficient to do two overlapping 8 byte copies than
- 8 + 4 + 2 + 1. */
- if (n > 0 && n < copy_limit / 2)
+ 8 + 4 + 2 + 1. Only do this when -mstrict-align is not supplied. */
+ if (n > 0 && n < copy_limit / 2 && !STRICT_ALIGNMENT)
{
next_mode = smallest_mode_for_size (n, MODE_INT);
int n_bits = GET_MODE_BITSIZE (next_mode).to_constant ();
diff --git a/gcc/testsuite/gcc.target/aarch64/memset-strict-align-1.c
b/gcc/testsuite/gcc.target/aarch64/memset-strict-align-1.c
new file mode 100644
index 00000000000..5cdc8a44968
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/memset-strict-align-1.c
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Os -mstrict-align" } */
+
+struct s { char x[95]; };
+void foo (struct s *);
+void bar (void) { struct s s1 = {}; foo (&s1); }
+
+/* memset (s1 = {}, sizeof = 95) should be expanded out
+ such that there are no overlap stores when -mstrict-align
+ is in use.
+ so 2 pair 16 bytes stores (64 bytes).
+ 1 16 byte stores
+ 1 8 byte store
+ 1 4 byte store
+ 1 2 byte store
+ 1 1 byte store
+ */
+
+/* { dg-final { scan-assembler-times "stp\tq" 2 } } */
+/* { dg-final { scan-assembler-times "str\tq" 1 } } */
+/* { dg-final { scan-assembler-times "str\txzr" 1 } } */
+/* { dg-final { scan-assembler-times "str\twzr" 1 } } */
+/* { dg-final { scan-assembler-times "strh\twzr" 1 } } */
+/* { dg-final { scan-assembler-times "strb\twzr" 1 } } */
+
+/* Also one store pair for the frame-pointer and the LR. */
+/* { dg-final { scan-assembler-times "stp\tx" 1 } } */
+
--
2.17.1
