llvm-6502/longlong-deadload.ll at 84b7df43fb098268f6ce37a3e32bcc2f455ecf96 - llvm-6502 - Applefritter: Git

6502/llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-30 02:32:08 +00:00

Chris Lattner 07649d9265 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



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45762 91177308-0d34-0410-b5e6-96231b3b80d8

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

12 lines

301 B

LLVM

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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
 }