v2: Tweak testsuite options to avoid failures
GCC currently defaults to -fcommon. As discussed in the PR, this is an ancient
C feature which is not conforming with the latest C standards. On many targets
this means global variable accesses have a codesize and performance penalty.
This applies to C code only, C++ code is not affected by -fcommon. It is about
time to change the default.
Bootstrap OK, passes testsuite on AArch64. OK for commit?
ChangeLog
2019-10-29 Wilco Dijkstra <wdijk...@arm.com>
PR85678
* common.opt (fcommon): Change init to 1.
doc/
* invoke.texi (-fcommon): Update documentation.
testsuite/
* gcc.dg/alias-15.c: Add -fcommon.
* gcc.dg/fdata-sections-1.c: Likewise.
* gcc.dg/ipa/pr77653.c: Likewise.
* gcc.dg/lto/20090729_0.c: Likewise.
* gcc.dg/lto/20111207-1_0.c: Likewise.
* gcc.dg/lto/c-compatible-types-1_0.c: Likewise.
* gcc.dg/lto/pr55525_0.c: Likewise.
* gcc.target/aarch64/sve/peel_ind_1.c: Allow ANCHOR0.
* gcc.target/aarch64/sve/peel_ind_2.c: Likewise
* gcc.target/aarch64/sve/peel_ind_3.c: Likewise
* lib/lto.exp (lto_init): Add -fcommon.
---
diff --git a/gcc/common.opt b/gcc/common.opt
index
f74b10aafc223e4961915b009c092f4876eddba4..798b6aeff3536e21c95752b5dd085f8ffef04643
100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1131,7 +1131,7 @@ Common Report Var(flag_combine_stack_adjustments)
Optimization
Looks for opportunities to reduce stack adjustments and stack references.
fcommon
-Common Report Var(flag_no_common,0)
+Common Report Var(flag_no_common,0) Init(1)
Put uninitialized globals in the common section.
fcompare-debug
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index
92fb316a368a4a36218fac6de2744c7ab6446ef5..18cfd07d4bbb4b866808db0701faf88bddbd9a94
100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -568,7 +568,7 @@ Objective-C and Objective-C++ Dialects}.
-fnon-call-exceptions -fdelete-dead-exceptions -funwind-tables @gol
-fasynchronous-unwind-tables @gol
-fno-gnu-unique @gol
--finhibit-size-directive -fno-common -fno-ident @gol
+-finhibit-size-directive -fcommon -fno-ident @gol
-fpcc-struct-return -fpic -fPIC -fpie -fPIE -fno-plt @gol
-fno-jump-tables @gol
-frecord-gcc-switches @gol
@@ -14049,35 +14049,27 @@ useful for building programs to run under WINE@.
code that is not binary compatible with code generated without that switch.
Use it to conform to a non-default application binary interface.
-@item -fno-common
-@opindex fno-common
+@item -fcommon
@opindex fcommon
+@opindex fno-common
@cindex tentative definitions
-In C code, this option controls the placement of global variables
-defined without an initializer, known as @dfn{tentative definitions}
-in the C standard. Tentative definitions are distinct from declarations
+In C code, this option controls the placement of global variables
+defined without an initializer, known as @dfn{tentative definitions}
+in the C standard. Tentative definitions are distinct from declarations
of a variable with the @code{extern} keyword, which do not allocate storage.
-Unix C compilers have traditionally allocated storage for
-uninitialized global variables in a common block. This allows the
-linker to resolve all tentative definitions of the same variable
+The default is @option{-fno-common}, which specifies that the compiler places
+uninitialized global variables in the BSS section of the object file.
+This inhibits the merging of tentative definitions by the linker so you get a
+multiple-definition error if the same variable is accidentally defined in more
+than one compilation unit.
+
+The @option{-fcommon} places uninitialized global variables in a common block.
+This allows the linker to resolve all tentative definitions of the same
variable
in different compilation units to the same object, or to a non-tentative
-definition.
-This is the behavior specified by @option{-fcommon}, and is the default for
-GCC on most targets.
-On the other hand, this behavior is not required by ISO
-C, and on some targets may carry a speed or code size penalty on
-variable references.
-
-The @option{-fno-common} option specifies that the compiler should instead
-place uninitialized global variables in the BSS section of the object file.
-This inhibits the merging of tentative definitions by the linker so
-you get a multiple-definition error if the same
-variable is defined in more than one compilation unit.
-Compiling with @option{-fno-common} is useful on targets for which
-it provides better performance, or if you wish to verify that the
-program will work on other systems that always treat uninitialized
-variable definitions this way.
+definition. This behavior does not conform to ISO C, is inconsistent with C++,
+and on many targets implies a speed and code size penalty on global variable
+references. It is mainly useful to enable legacy code to link without errors.
@item -fno-ident
@opindex fno-ident
diff --git a/gcc/testsuite/gcc.dg/alias-15.c b/gcc/testsuite/gcc.dg/alias-15.c
index
0a8e69b61eceef95e61f16d7874b5a4204e0594f..304ad1fbaeb7fe68ef26efd31c2ee545db6a0ffc
100644
--- a/gcc/testsuite/gcc.dg/alias-15.c
+++ b/gcc/testsuite/gcc.dg/alias-15.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-additional-options "-O2 -fdump-ipa-cgraph" } */
+/* { dg-additional-options "-O2 -fcommon -fdump-ipa-cgraph" } */
/* RTL-level CSE shouldn't introduce LCO (for the string) into varpool */
char *p;
diff --git a/gcc/testsuite/gcc.dg/fdata-sections-1.c
b/gcc/testsuite/gcc.dg/fdata-sections-1.c
index
e8a6639f32e38fdb539232288c92000f000ca79e..de5ddfc0179a588ce1bdb3d5f39a14438823c071
100644
--- a/gcc/testsuite/gcc.dg/fdata-sections-1.c
+++ b/gcc/testsuite/gcc.dg/fdata-sections-1.c
@@ -2,7 +2,7 @@
/* Origin: Jonathan Larmour <jifl-bugzi...@jifvik.org> */
/* { dg-do compile { target *-*-linux* *-*-gnu* *-*-uclinux* } } */
-/* { dg-options "-fdata-sections" } */
+/* { dg-options "-fcommon -fdata-sections" } */
int x;
diff --git a/gcc/testsuite/gcc.dg/ipa/pr77653.c
b/gcc/testsuite/gcc.dg/ipa/pr77653.c
index
f0b2b224091583bcf51d8d7444033c2042de3b7b..2fddb7eab548690a7a9d2edb3172c2b17ff9ea63
100644
--- a/gcc/testsuite/gcc.dg/ipa/pr77653.c
+++ b/gcc/testsuite/gcc.dg/ipa/pr77653.c
@@ -1,5 +1,5 @@
/* { dg-require-alias "" } */
-/* { dg-options "-O2 -fdump-ipa-icf-details" } */
+/* { dg-options "-O2 -fcommon -fdump-ipa-icf-details" } */
int a, b, c, d, e, h, i, j, k, l;
const int f;
diff --git a/gcc/testsuite/gcc.dg/lto/20090729_0.c
b/gcc/testsuite/gcc.dg/lto/20090729_0.c
index
05ae74f872e28c417a8032688b3c75cd38eb6f6f..13fe62b5923b7c868373d8ca269730aa588d4992
100644
--- a/gcc/testsuite/gcc.dg/lto/20090729_0.c
+++ b/gcc/testsuite/gcc.dg/lto/20090729_0.c
@@ -1,4 +1,4 @@
-/* { dg-lto-options "-w" } */
+/* { dg-lto-options { {-fcommon -w} {-fcommon} } } */
double i;
int j;
diff --git a/gcc/testsuite/gcc.dg/lto/20111207-1_0.c
b/gcc/testsuite/gcc.dg/lto/20111207-1_0.c
index
486264066f6fcab4a248fd6293af2b6cae65caf5..5f11264af17a5a50c6d27e6eb8667bbdfce131f1
100644
--- a/gcc/testsuite/gcc.dg/lto/20111207-1_0.c
+++ b/gcc/testsuite/gcc.dg/lto/20111207-1_0.c
@@ -1,4 +1,4 @@
/* { dg-lto-do run } */
-/* { dg-lto-options { { -flto } } } */
+/* { dg-lto-options { { -flto -fcommon } {-fcommon} {-fcommon} {-fcommon} } }
*/
/* { dg-require-linker-plugin "" } */
/* { dg-extra-ld-options "-fuse-linker-plugin" } */
diff --git a/gcc/testsuite/gcc.dg/lto/c-compatible-types-1_0.c
b/gcc/testsuite/gcc.dg/lto/c-compatible-types-1_0.c
index
376da00599d04a738b8b5d6c6d3625d915cae83b..45b03735a6befd47b5b24cab5c62ecc8792aed4c
100644
--- a/gcc/testsuite/gcc.dg/lto/c-compatible-types-1_0.c
+++ b/gcc/testsuite/gcc.dg/lto/c-compatible-types-1_0.c
@@ -1,5 +1,5 @@
/* { dg-lto-do run } */
-/* { dg-lto-options "-O3" } */
+/* { dg-lto-options { {-O3 -fcommon} {-fcommon} } } */
/* By C standard Each enumerated type shall be compatible with char, a signed
integer, type, or an unsigned integer type. The choice of type is
diff --git a/gcc/testsuite/gcc.dg/lto/pr55525_0.c
b/gcc/testsuite/gcc.dg/lto/pr55525_0.c
index
7faaf806a75836be4eb9a3ede7559dd4d4151185..d8d16d11d32d3918bc47f4b41c7e7dabe255fd39
100644
--- a/gcc/testsuite/gcc.dg/lto/pr55525_0.c
+++ b/gcc/testsuite/gcc.dg/lto/pr55525_0.c
@@ -1,5 +1,5 @@
/* { dg-lto-do link } */
-/* { dg-lto-options { { -flto -w } } } */
+/* { dg-lto-options { { -fcommon -flto -w } } } */
char s[sizeof (char *)];
int main(void)
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_1.c
b/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_1.c
index
156d04ae5ca222ddea3e12a3b785050c6113a548..e9afc2047e49e4382fd2cc5b150de51be89e2e3d
100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_1.c
@@ -21,7 +21,7 @@ foo (void)
}
/* We should operate on aligned vectors. */
-/* { dg-final { scan-assembler {\t(adrp|adr)\tx[0-9]+, x\n} } } */
+/* { dg-final { scan-assembler {\t(adrp|adr)\tx[0-9]+, (x|\.LANCHOR0)\n} } } */
/* We should use an induction that starts at -5, with only the last
7 elements of the first iteration being active. */
/* { dg-final { scan-assembler {\tindex\tz[0-9]+\.s, #-5, #5\n} } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_2.c
b/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_2.c
index
e792cdf2cad297e7044fdecd576343c9ac212078..6bd7fc73fb03d339b17c62d1ad818c9bdb351e1b
100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_2.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_2.c
@@ -17,7 +17,7 @@ foo (void)
}
/* We should operate on aligned vectors. */
-/* { dg-final { scan-assembler {\t(adrp|adr)\tx[0-9]+, x\n} } } */
+/* { dg-final { scan-assembler {\t(adrp|adr)\tx[0-9]+, (x|\.LANCHOR0)\n} } } */
/* We should unroll the loop three times. */
/* { dg-final { scan-assembler-times "\tst1w\t" 3 } } */
/* { dg-final { scan-assembler {\tptrue\t(p[0-9]+)\.s,
vl7\n.*\teor\tp[0-7]\.b, (p[0-7])/z, (\1\.b, \2\.b|\2\.b, \1\.b)\n} } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_3.c
b/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_3.c
index
441589eef600df0d1b264780774a9bdc4deb975e..3adddf3f4049a73bae99ab3468f83c535ef55170
100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_3.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/peel_ind_3.c
@@ -17,5 +17,5 @@ foo (int start)
}
/* We should operate on aligned vectors. */
-/* { dg-final { scan-assembler {\t(adrp|adr)\tx[0-9]+, x\n} } } */
+/* { dg-final { scan-assembler {\t(adrp|adr)\tx[0-9]+, (x|\.LANCHOR0)\n} } } */
/* { dg-final { scan-assembler {\tubfx\t} } } */
diff --git a/gcc/testsuite/lib/lto.exp b/gcc/testsuite/lib/lto.exp
index
25c934731df0bb94f2e61561142f75438c4294fa..e931f946ad2537a53a45e1855513fb4d1682351c
100644
--- a/gcc/testsuite/lib/lto.exp
+++ b/gcc/testsuite/lib/lto.exp
@@ -191,21 +191,21 @@ proc lto_init { args } {
if ![info exists LTO_OPTIONS] {
if [check_linker_plugin_available] {
set LTO_OPTIONS [list \
- {-O0 -flto -flto-partition=none -fuse-linker-plugin} \
- {-O2 -flto -flto-partition=none -fuse-linker-plugin
-fno-fat-lto-objects } \
- {-O0 -flto -flto-partition=1to1 -fno-use-linker-plugin } \
- {-O2 -flto -flto-partition=1to1 -fno-use-linker-plugin } \
- {-O0 -flto -fuse-linker-plugin -fno-fat-lto-objects } \
- {-O2 -flto -fuse-linker-plugin} \
+ {-O0 -flto -fcommon -flto-partition=none -fuse-linker-plugin} \
+ {-O2 -flto -fcommon -flto-partition=none -fuse-linker-plugin
-fno-fat-lto-objects } \
+ {-O0 -flto -fcommon -flto-partition=1to1 -fno-use-linker-plugin }
\
+ {-O2 -flto -fcommon -flto-partition=1to1 -fno-use-linker-plugin }
\
+ {-O0 -flto -fcommon -fuse-linker-plugin -fno-fat-lto-objects }
\
+ {-O2 -flto -fcommon -fuse-linker-plugin} \
]
} else {
set LTO_OPTIONS [list \
- {-O0 -flto -flto-partition=none } \
- {-O2 -flto -flto-partition=none } \
- {-O0 -flto -flto-partition=1to1 } \
- {-O2 -flto -flto-partition=1to1 } \
- {-O0 -flto } \
- {-O2 -flto} \
+ {-O0 -flto -fcommon -flto-partition=none } \
+ {-O2 -flto -fcommon -flto-partition=none } \
+ {-O0 -flto -fcommon -flto-partition=1to1 } \
+ {-O2 -flto -fcommon -flto-partition=1to1 } \
+ {-O0 -flto -fcommon} \
+ {-O2 -flto -fcommon} \
]
}
}
