From 49813aad3292f7f2bef69206274da78a9a7116ed Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 16 Apr 2021 20:49:33 +0200
Subject: [PATCH] aarch64: Don't emit -Wpsabi note when ABI was never affected
[PR91710]
As the following testcase shows, we emit a -Wpsabi note about argument
passing change since GCC 9, but in reality the ABI didn't change.
The alignment is 8 bits in GCC < 9 and 32 bits in GCC >= 9 and
the aarch64_function_arg_alignment returns in that case:
return MIN (MAX (alignment, PARM_BOUNDARY), STACK_BOUNDARY);
so when both the old and new alignment are smaller or equal to PARM_BOUNDARY
(or both are larger than STACK_BOUNDARY, just in theory), even when the new
one is bigger, it doesn't change the argument passing.
So, the following patch changes aarch64_function_arg_alignment to tell the
callers the exact old alignmentm so that they can test it if needed.
The other aarch64_function_arg_alignment callers either check the
alignment for equality against 16-byte alignment (when old alignment was
smaller than that and the new one is 16-byte, we want to emit -Wpsabi
in all the cases) or the va_arg case which I think is ok now too.
2021-04-16 Jakub Jelinek <jakub@redhat.com>
PR target/91710
* config/aarch64/aarch64.c (aarch64_function_arg_alignment): Change
abi_break argument from bool * to unsigned *, store there the pre-GCC 9
alignment.
(aarch64_layout_arg, aarch64_gimplify_va_arg_expr): Adjust callers.
(aarch64_function_arg_regno_p): Likewise. Only emit -Wpsabi note if
the old and new alignment after applying MIN/MAX to it is different.
* gcc.target/aarch64/pr91710.c: New test.
---
gcc/config/aarch64/aarch64.c | 23 +++++++++++++---------
gcc/testsuite/gcc.target/aarch64/pr91710.c | 16 +++++++++++++++
2 files changed, 30 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/pr91710.c
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 09d79f67a61e..12625a4bee39 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -6337,9 +6337,9 @@ aarch64_vfp_is_call_candidate (cumulative_args_t pcum_v, machine_mode mode,
static unsigned int
aarch64_function_arg_alignment (machine_mode mode, const_tree type,
- bool *abi_break)
+ unsigned int *abi_break)
{
- *abi_break = false;
+ *abi_break = 0;
if (!type)
return GET_MODE_ALIGNMENT (mode);
@@ -6381,7 +6381,7 @@ aarch64_function_arg_alignment (machine_mode mode, const_tree type,
if (bitfield_alignment > alignment)
{
- *abi_break = true;
+ *abi_break = alignment;
return bitfield_alignment;
}
@@ -6403,7 +6403,7 @@ aarch64_layout_arg (cumulative_args_t pcum_v, const function_arg_info &arg)
int ncrn, nvrn, nregs;
bool allocate_ncrn, allocate_nvrn;
HOST_WIDE_INT size;
- bool abi_break;
+ unsigned int abi_break;
/* We need to do this once per argument. */
if (pcum->aapcs_arg_processed)
@@ -6721,14 +6721,19 @@ aarch64_function_arg_regno_p (unsigned regno)
static unsigned int
aarch64_function_arg_boundary (machine_mode mode, const_tree type)
{
- bool abi_break;
+ unsigned int abi_break;
unsigned int alignment = aarch64_function_arg_alignment (mode, type,
&abi_break);
+ alignment = MIN (MAX (alignment, PARM_BOUNDARY), STACK_BOUNDARY);
if (abi_break & warn_psabi)
- inform (input_location, "parameter passing for argument of type "
- "%qT changed in GCC 9.1", type);
+ {
+ abi_break = MIN (MAX (abi_break, PARM_BOUNDARY), STACK_BOUNDARY);
+ if (alignment != abi_break)
+ inform (input_location, "parameter passing for argument of type "
+ "%qT changed in GCC 9.1", type);
+ }
- return MIN (MAX (alignment, PARM_BOUNDARY), STACK_BOUNDARY);
+ return alignment;
}
/* Implement TARGET_GET_RAW_RESULT_MODE and TARGET_GET_RAW_ARG_MODE. */
@@ -18253,7 +18258,7 @@ aarch64_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p,
f_stack, NULL_TREE);
size = int_size_in_bytes (type);
- bool abi_break;
+ unsigned int abi_break;
align
= aarch64_function_arg_alignment (mode, type, &abi_break) / BITS_PER_UNIT;
diff --git a/gcc/testsuite/gcc.target/aarch64/pr91710.c b/gcc/testsuite/gcc.target/aarch64/pr91710.c
new file mode 100644
index 000000000000..496eb505a712
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr91710.c
@@ -0,0 +1,16 @@
+/* PR target/91710 */
+/* { dg-do compile } */
+
+struct S { unsigned int i:4; };
+
+unsigned int test1(struct S s) { /* { dg-bogus "parameter passing for argument of type" } */
+ return s.i;
+}
+
+unsigned int test2(unsigned x, struct S s) { /* { dg-bogus "parameter passing for argument of type" } */
+ return x - s.i;
+}
+
+unsigned int test3(unsigned x, unsigned y, struct S s) { /* { dg-bogus "parameter passing for argument of type" } */
+ return x - y - s.i;
+}
--
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