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[llvm-gcc] llvm-gcc lays out bitfields backwards on big endian systems #966

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lattner opened this issue Jul 14, 2005 · 2 comments
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bugzilla Issues migrated from bugzilla llvm-tools All llvm tools that do not have corresponding tag miscompilation

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@lattner
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lattner commented Jul 14, 2005

Bugzilla Link 594
Resolution FIXED
Resolved on Feb 22, 2010 12:51
Version 1.0
OS MacOS X

Extended Description

This program is miscompiled by LLVM on powerpc. It appears that bitfields are
being layed out backwards by the CFE. This may be related to Bug 449. It
probably also affects Sparc. This testcase should be compiled with
-fno-strict-aliasing.

-Chris

struct X {
int A : 4;
int Z : 28;
};

void test(struct X *P, int A) {
P->A = A;
}

int main() {
int Y = ~0;
test((struct X*)&Y, 0);
printf("%x\n", Y);
}

@lattner
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lattner commented Jul 14, 2005

assigned to @lattner

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lattner commented Jul 21, 2005

@llvmbot llvmbot transferred this issue from llvm/llvm-bugzilla-archive Dec 3, 2021
This issue was closed.
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Labels
bugzilla Issues migrated from bugzilla llvm-tools All llvm tools that do not have corresponding tag miscompilation
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