Hello,
this is the variant intended for the 4.8/4.9 branches of the patch:
https://gcc.gnu.org/ml/gcc-patches/2014-07/msg01072.html
As discussed, it does *not* actually change ABI, but only warn when
encountering a situation where the ABI will change in a future GCC.
(Avoiding the specific term "GCC 4.10" here since I'm not certain
whether the next GCC release will in fact be called that ...)
Tested on powerpc64-linux and powerpc64le-linux; also verified using
the ABI compat suite (against an unpatched GCC) that this patch does
not change the ABI.
OK for 4.8/4.9 once the mainline patch is in?
Bye,
Ulrich
gcc/ChangeLog:
* config/rs6000/rs6000-protos.h (rs6000_special_adjust_field_align_p):
Add prototype.
* config/rs6000/rs6000.c (rs6000_special_adjust_field_align_p): New
function. Issue -Wpsabi warning if future GCC releases will use
different field alignment rules for this type.
* config/rs6000/sysv4.h (ADJUST_FIELD_ALIGN): Call it.
* config/rs6000/linux64.h (ADJUST_FIELD_ALIGN): Likewise.
* config/rs6000/freebsd64.h (ADJUST_FIELD_ALIGN): Likewise.
gcc/testsuite/ChangeLog:
* gcc.target/powerpc/ppc64-abi-warn-3.c: New test.
* gcc.c-torture/execute/20050316-1.x: Add -Wno-psabi.
* gcc.c-torture/execute/20050604-1.x: Add -Wno-psabi.
* gcc.c-torture/execute/20050316-3.x: New file. Add -Wno-psabi.
* gcc.c-torture/execute/pr23135.x: Likewise.
Index: gcc-4_9-branch/gcc/config/rs6000/rs6000-protos.h
===================================================================
--- gcc-4_9-branch.orig/gcc/config/rs6000/rs6000-protos.h
+++ gcc-4_9-branch/gcc/config/rs6000/rs6000-protos.h
@@ -155,6 +155,7 @@ extern void rs6000_split_logical (rtx []
#ifdef TREE_CODE
extern unsigned int rs6000_data_alignment (tree, unsigned int, enum
data_align);
+extern bool rs6000_special_adjust_field_align_p (tree, unsigned int);
extern unsigned int rs6000_special_round_type_align (tree, unsigned int,
unsigned int);
extern unsigned int darwin_rs6000_special_round_type_align (tree, unsigned int,
Index: gcc-4_9-branch/gcc/config/rs6000/rs6000.c
===================================================================
--- gcc-4_9-branch.orig/gcc/config/rs6000/rs6000.c
+++ gcc-4_9-branch/gcc/config/rs6000/rs6000.c
@@ -5871,6 +5871,34 @@ rs6000_data_alignment (tree type, unsign
return align;
}
+/* Previous GCC releases forced all vector types to have 16-byte alignment. */
+
+bool
+rs6000_special_adjust_field_align_p (tree field, unsigned int computed)
+{
+ if (TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (field)) == VECTOR_TYPE)
+ {
+ if (computed != 128)
+ {
+ static bool warned;
+ if (!warned && warn_psabi)
+ {
+ warned = true;
+ inform (input_location,
+ "the layout of aggregates containing vectors with"
+ " %d-byte alignment will change in a future GCC release",
+ computed / BITS_PER_UNIT);
+ }
+ }
+ /* GCC 4.8/4.9 Note: To avoid any ABI change on a release branch, we
+ keep the special treatment of vector types, but warn if there will
+ be differences in future GCC releases. */
+ return true;
+ }
+
+ return false;
+}
+
/* AIX increases natural record alignment to doubleword if the first
field is an FP double while the FP fields remain word aligned. */
Index: gcc-4_9-branch/gcc/config/rs6000/sysv4.h
===================================================================
--- gcc-4_9-branch.orig/gcc/config/rs6000/sysv4.h
+++ gcc-4_9-branch/gcc/config/rs6000/sysv4.h
@@ -292,7 +292,7 @@ do {
\
/* An expression for the alignment of a structure field FIELD if the
alignment computed in the usual way is COMPUTED. */
#define ADJUST_FIELD_ALIGN(FIELD, COMPUTED) \
- ((TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (FIELD)) == VECTOR_TYPE) \
+ (rs6000_special_adjust_field_align_p ((FIELD), (COMPUTED)) \
? 128 : COMPUTED)
#undef BIGGEST_FIELD_ALIGNMENT
Index: gcc-4_9-branch/gcc/config/rs6000/linux64.h
===================================================================
--- gcc-4_9-branch.orig/gcc/config/rs6000/linux64.h
+++ gcc-4_9-branch/gcc/config/rs6000/linux64.h
@@ -246,7 +246,7 @@ extern int dot_symbols;
/* PowerPC64 Linux word-aligns FP doubles when -malign-power is given. */
#undef ADJUST_FIELD_ALIGN
#define ADJUST_FIELD_ALIGN(FIELD, COMPUTED) \
- ((TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (FIELD)) == VECTOR_TYPE) \
+ (rs6000_special_adjust_field_align_p ((FIELD), (COMPUTED)) \
? 128 \
: (TARGET_64BIT \
&& TARGET_ALIGN_NATURAL == 0 \
Index: gcc-4_9-branch/gcc/config/rs6000/freebsd64.h
===================================================================
--- gcc-4_9-branch.orig/gcc/config/rs6000/freebsd64.h
+++ gcc-4_9-branch/gcc/config/rs6000/freebsd64.h
@@ -367,7 +367,7 @@ extern int dot_symbols;
/* PowerPC64 Linux word-aligns FP doubles when -malign-power is given. */
#undef ADJUST_FIELD_ALIGN
#define ADJUST_FIELD_ALIGN(FIELD, COMPUTED) \
- ((TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (FIELD)) == VECTOR_TYPE) \
+ (rs6000_special_adjust_field_align_p ((FIELD), (COMPUTED)) \
? 128 \
: (TARGET_64BIT \
&& TARGET_ALIGN_NATURAL == 0 \
Index: gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/20050316-1.x
===================================================================
--- gcc-4_9-branch.orig/gcc/testsuite/gcc.c-torture/execute/20050316-1.x
+++ gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/20050316-1.x
@@ -4,4 +4,5 @@ if { [check_effective_target_int16] } {
return 1
}
+set additional_flags "-Wno-psabi"
return 0;
Index: gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/20050316-3.x
===================================================================
--- /dev/null
+++ gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/20050316-3.x
@@ -0,0 +1,2 @@
+set additional_flags "-Wno-psabi"
+return 0
Index: gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/20050604-1.x
===================================================================
--- gcc-4_9-branch.orig/gcc/testsuite/gcc.c-torture/execute/20050604-1.x
+++ gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/20050604-1.x
@@ -6,4 +6,5 @@ if { [istarget "i?86-*-*"] || [istarget
set additional_flags "-mno-mmx"
}
+set additional_flags "-Wno-psabi"
return 0
Index: gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/pr23135.x
===================================================================
--- /dev/null
+++ gcc-4_9-branch/gcc/testsuite/gcc.c-torture/execute/pr23135.x
@@ -0,0 +1,2 @@
+set additional_flags "-Wno-psabi"
+return 0
Index: gcc-4_9-branch/gcc/testsuite/gcc.target/powerpc/ppc64-abi-warn-3.c
===================================================================
--- /dev/null
+++ gcc-4_9-branch/gcc/testsuite/gcc.target/powerpc/ppc64-abi-warn-3.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target { powerpc*-*-linux* && lp64 } } } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-options "-maltivec" } */
+
+struct test
+ {
+ int a __attribute__((vector_size (8)));
+ }; /* { dg-message "note: the layout of aggregates containing vectors with
8-byte alignment will change" } */
+
--
Dr. Ulrich Weigand
GNU/Linux compilers and toolchain
ulrich.weig...@de.ibm.com
