On 27/03/18 13:58, Sudakshina Das wrote:
Hi
This patch adds the no variant to -mstrict-align and the corresponding
function attribute. To enable the function attribute, I have modified
aarch64_can_inline_p () to allow checks even when the callee function
has no attribute. The need for this is shown by the new test
target_attr_18.c.
Testing: Bootstrapped, regtested and added new tests that are copies
of earlier tests checking -mstrict-align with opposite scan directives.
Is this ok for trunk?
Sudi
*** gcc/ChangeLog ***
2018-03-27 Sudakshina Das <sudi....@arm.com>
* common/config/aarch64/aarch64-common.c (aarch64_handle_option):
Check val before adding MASK_STRICT_ALIGN to opts->x_target_flags.
* config/aarch64/aarch64.opt (mstrict-align): Remove RejectNegative.
* config/aarch64/aarch64.c (aarch64_attributes): Mark allow_neg
as true for strict-align.
(aarch64_can_inline_p): Perform checks even when callee has no
attributes to check for strict alignment.
* doc/extend.texi (AArch64 Function Attributes): Document
no-strict-align.
* doc/invoke.texi: (AArch64 Options): Likewise.
*** gcc/testsuite/ChangeLog ***
2018-03-27 Sudakshina Das <sudi....@arm.com>
* gcc.target/aarch64/pr84882.c: New test.
* gcc.target/aarch64/target_attr_18.c: Likewise.
strict-align.diff
diff --git a/gcc/common/config/aarch64/aarch64-common.c
b/gcc/common/config/aarch64/aarch64-common.c
index 7fd9305..d5655a0 100644
--- a/gcc/common/config/aarch64/aarch64-common.c
+++ b/gcc/common/config/aarch64/aarch64-common.c
@@ -97,7 +97,10 @@ aarch64_handle_option (struct gcc_options *opts,
return true;
case OPT_mstrict_align:
- opts->x_target_flags |= MASK_STRICT_ALIGN;
+ if (val)
+ opts->x_target_flags |= MASK_STRICT_ALIGN;
+ else
+ opts->x_target_flags &= ~MASK_STRICT_ALIGN;
return true;
case OPT_momit_leaf_frame_pointer:
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 4b5183b..4f35a6c 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -11277,7 +11277,7 @@ static const struct aarch64_attribute_info
aarch64_attributes[] =
{ "fix-cortex-a53-843419", aarch64_attr_bool, true, NULL,
OPT_mfix_cortex_a53_843419 },
{ "cmodel", aarch64_attr_enum, false, NULL, OPT_mcmodel_ },
- { "strict-align", aarch64_attr_mask, false, NULL, OPT_mstrict_align },
+ { "strict-align", aarch64_attr_mask, true, NULL, OPT_mstrict_align },
{ "omit-leaf-frame-pointer", aarch64_attr_bool, true, NULL,
OPT_momit_leaf_frame_pointer },
{ "tls-dialect", aarch64_attr_enum, false, NULL, OPT_mtls_dialect_ },
@@ -11640,16 +11640,13 @@ aarch64_can_inline_p (tree caller, tree callee)
tree caller_tree = DECL_FUNCTION_SPECIFIC_TARGET (caller);
tree callee_tree = DECL_FUNCTION_SPECIFIC_TARGET (callee);
- /* If callee has no option attributes, then it is ok to inline. */
- if (!callee_tree)
- return true;
I think it's still useful to spot the case where both callee_tree and
caller_tree are NULL. In that case both options will pick up
target_option_default_node and will always be compatible; so you can
short-circuit that case, which is the most likely scenario.
-
struct cl_target_option *caller_opts
= TREE_TARGET_OPTION (caller_tree ? caller_tree
: target_option_default_node);
- struct cl_target_option *callee_opts = TREE_TARGET_OPTION (callee_tree);
-
+ struct cl_target_option *callee_opts
+ = TREE_TARGET_OPTION (callee_tree ? callee_tree
+ : target_option_default_node);
/* Callee's ISA flags should be a subset of the caller's. */
if ((caller_opts->x_aarch64_isa_flags & callee_opts->x_aarch64_isa_flags)
diff --git a/gcc/config/aarch64/aarch64.opt b/gcc/config/aarch64/aarch64.opt
index 52eaf8c..1426b45 100644
--- a/gcc/config/aarch64/aarch64.opt
+++ b/gcc/config/aarch64/aarch64.opt
@@ -85,7 +85,7 @@ Target RejectNegative Joined Enum(cmodel)
Var(aarch64_cmodel_var) Init(AARCH64_C
Specify the code model.
mstrict-align
-Target Report RejectNegative Mask(STRICT_ALIGN) Save
+Target Report Mask(STRICT_ALIGN) Save
Don't assume that unaligned accesses are handled by the system.
momit-leaf-frame-pointer
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 93a0ebc..dcda216 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -3605,8 +3605,10 @@ for the command line option @option{-mcmodel=}.
@item strict-align
Other targets add an @itemx for the no-variant.
@cindex @code{strict-align} function attribute, AArch64
Indicates that the compiler should not assume that unaligned memory references
-are handled by the system. The behavior is the same as for the command-line
-option @option{-mstrict-align}.
+are handled by the system. To allow the compiler to assume that aligned memory
+references are handled by the system, the inverse attribute
+@code{no-strict-align} can be specified. The behavior is the same as for the
+command-line option @option{-mstrict-align} and @option{-mno-strict-align}.
You've two options now, so 'options'.
@item omit-leaf-frame-pointer
@cindex @code{omit-leaf-frame-pointer} function attribute, AArch64
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index feacd56..0574d21 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -596,7 +596,7 @@ Objective-C and Objective-C++ Dialects}.
@gccoptlist{-mabi=@var{name} -mbig-endian -mlittle-endian @gol
-mgeneral-regs-only @gol
-mcmodel=tiny -mcmodel=small -mcmodel=large @gol
--mstrict-align @gol
+-mstrict-align -mno-strict-align @gol
-momit-leaf-frame-pointer @gol
-mtls-dialect=desc -mtls-dialect=traditional @gol
-mtls-size=@var{size} @gol
@@ -14601,9 +14601,11 @@ Generate code for the large code model. This makes no
assumptions about
addresses and sizes of sections. Programs can be statically linked only.
@item -mstrict-align
+@itemx -mno-strict-align
@opindex mstrict-align
-Avoid generating memory accesses that may not be aligned on a natural object
-boundary as described in the architecture specification.
+@opindex mno-strict-align
+Avoid or allow generating memory accesses that may not be aligned on a natural
+object boundary as described in the architecture specification.
@item -momit-leaf-frame-pointer
@itemx -mno-omit-leaf-frame-pointer
diff --git a/gcc/testsuite/gcc.target/aarch64/pr84882.c
b/gcc/testsuite/gcc.target/aarch64/pr84882.c
new file mode 100644
index 0000000..ffc7d55
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr84882.c
@@ -0,0 +1,33 @@
+/* This is a copy of pr71727.c with scanning reversed. */
+/* { dg-do compile } */
+/* { dg-options "-mstrict-align -O3 -mno-strict-align" } */
+
+struct test_struct_s
+{
+ long a;
+ long b;
+ long c;
+ long d;
+ unsigned long e;
+};
+
+
+char _a;
+struct test_struct_s xarray[128];
+
+void
+_start (void)
+{
+ struct test_struct_s *new_entry;
+
+ new_entry = &xarray[0];
+ new_entry->a = 1;
+ new_entry->b = 2;
+ new_entry->c = 3;
+ new_entry->d = 4;
+ new_entry->e = 5;
+
+ return;
+}
+
+/* { dg-final { scan-assembler "add\tx[0-9]+, x[0-9]+, :" {target lp64} } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/target_attr_18.c
b/gcc/testsuite/gcc.target/aarch64/target_attr_18.c
new file mode 100644
index 0000000..33b1d44
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/target_attr_18.c
@@ -0,0 +1,21 @@
+/* This is a copy of target_attr_6.c to instead check no-strict-align. */
+/* { dg-do compile } */
+/* { dg-options "-O2 -save-temps -mstrict-align" } */
+
+/* Inlining strict-align functions into non-strict align
+ functions is not allowed. */
+
+int
+bar (int a)
+{
+ return a - 6;
+}
+
+__attribute__ ((target ("no-strict-align")))
+int
+bam (int a)
+{
+ return a - bar (a);
+}
+
+/* { dg-final { scan-assembler "bl.*bar" } } */
OK with those changes. As Kyrill said, don't forget the PR number in
the changelog.
