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[X86] This bit-test TODO has been moved in PR36551

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llvm-svn: 326658
This commit is contained in:
Simon Pilgrim 2018-03-03 16:31:17 +00:00
parent 2b16f40269
commit 6583c8a76b
1 changed files with 0 additions and 24 deletions
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24
lib/Target/X86/README.txt
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@ -1436,30 +1436,6 @@ bar:
//===---------------------------------------------------------------------===//
Consider the following two functions compiled with clang:
_Bool foo(int *x) { return !(*x & 4); }
unsigned bar(int *x) { return !(*x & 4); }
foo:
movl 4(%esp), %eax
testb $4, (%eax)
sete %al
movzbl %al, %eax
ret
bar:
movl 4(%esp), %eax
movl (%eax), %eax
shrl $2, %eax
andl $1, %eax
xorl $1, %eax
ret
The second function generates more code even though the two functions are
are functionally identical.
//===---------------------------------------------------------------------===//
Take the following C code:
int f(int a, int b) { return (unsigned char)a == (unsigned char)b; }