llvm-mirror/longlong-deadload.ll at b64f2c1b08e18fcc353ab75024377dc6564a84af - llvm-mirror - Git.je (Gitea)

RPCS3/llvm-mirror

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Chris Lattner c93ad7d569 Make load->store deletion a bit smarter. This allows us to compile this:

void test(long long *P) { *P ^= 1; }

into just:

_test:
	movl	4(%esp), %eax
	xorl	$1, (%eax)
	ret

instead of code like this:

_test:
	movl	4(%esp), %ecx
        xorl    $1, (%ecx)
	movl	4(%ecx), %edx
	movl	%edx, 4(%ecx)
	ret

llvm-svn: 45762

2008-01-08 23:08:06 +00:00

12 lines

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 ; RUN: llvm-as < %s | llc -march=x86 | not grep '4{(%...)}
 ; This should not load or store the top part of *P.
 define void @test(i64* %P) nounwind  {
 entry:
 	%tmp1 = load i64* %P, align 8		; <i64> [#uses=1]
 	%tmp2 = xor i64 %tmp1, 1		; <i64> [#uses=1]
 	store i64 %tmp2, i64* %P, align 8
 	ret void
 }