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gcc/clang treat __attribute__((aligned())) differently #2376

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Merged
merged 1 commit into from
Jun 21, 2018
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gcc/clang treat __attribute__((aligned())) differently #2376

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34 changes: 21 additions & 13 deletions regression/ansi-c/gcc_attributes5/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3,21 +3,29 @@

#ifdef __GNUC__

char __attribute__((aligned(8))) var1;
__attribute__((aligned(8))) char var2;
char var3 __attribute__((aligned(8)));
int (__attribute__((aligned(8))) var4);
int (__attribute__((aligned(8))) (var5));
int (__attribute__((aligned(8))) *var6);
int __attribute__((aligned(8))) *var7;
char __attribute__((aligned(16))) var1;
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I don't really understand why various alignments are changed from 8 to 16? All I would have expected is the #ifdef __clang part below.

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The reason that the test has passed so far was a bit random: the default alignment of pointers on 64-bit machines is 8. Using 16 avoids that coincidence.

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Ok, could you please add that to the commit message?

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Done

__attribute__((aligned(16))) char var2;
char var3 __attribute__((aligned(16)));
int (__attribute__((aligned(16))) var4);
int (__attribute__((aligned(16))) (var5));
int (__attribute__((aligned(16))) *var6);
int __attribute__((aligned(16))) *var7;
__attribute__((aligned(16))) int *var8;

STATIC_ASSERT(__alignof(var1)==8);
STATIC_ASSERT(__alignof(var2)==8);
STATIC_ASSERT(__alignof(var3)==8);
STATIC_ASSERT(__alignof(var4)==8);
STATIC_ASSERT(__alignof(var5)==8);
STATIC_ASSERT(__alignof(var1)==16);
STATIC_ASSERT(__alignof(var2)==16);
STATIC_ASSERT(__alignof(var3)==16);
STATIC_ASSERT(__alignof(var4)==16);
STATIC_ASSERT(__alignof(var5)==16);
#ifdef __clang__
STATIC_ASSERT(__alignof(var6)==16);
STATIC_ASSERT(__alignof(*var6)==__alignof(int));
#else
STATIC_ASSERT(__alignof(var6)==__alignof(void *));
STATIC_ASSERT(__alignof(var7)==8);
STATIC_ASSERT(__alignof(*var6)==16);
#endif
STATIC_ASSERT(__alignof(var7)==16);
STATIC_ASSERT(__alignof(var8)==16);

void (__attribute__((aligned)) *****f1)(void);
void (__attribute__((aligned)) f2)(void);
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2 changes: 1 addition & 1 deletion regression/ansi-c/gcc_attributes5/test.desc
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@@ -1,4 +1,4 @@
CORE gcc-only
KNOWNBUG gcc-only
main.c

^EXIT=0$
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