2009-09-09 07:54:48 +08:00
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; RUN: llc < %s -march=x86 > %t
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2009-03-18 07:43:59 +08:00
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; RUN: grep {movb.7(%...)} %t
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; RUN: not grep leal %t
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Teach CodeGenPrepare to look through Bitcast instructions when attempting to
optimize addressing modes. This allows us to optimize things like isel-sink2.ll
into:
movl 4(%esp), %eax
cmpb $0, 4(%eax)
jne LBB1_2 ## F
LBB1_1: ## TB
movl $4, %eax
ret
LBB1_2: ## F
movzbl 7(%eax), %eax
ret
instead of:
_test:
movl 4(%esp), %eax
cmpb $0, 4(%eax)
leal 4(%eax), %eax
jne LBB1_2 ## F
LBB1_1: ## TB
movl $4, %eax
ret
LBB1_2: ## F
movzbl 3(%eax), %eax
ret
This shrinks (e.g.) 403.gcc from 1133510 to 1128345 lines of .s.
Note that the 2008-10-16-SpillerBug.ll testcase is dubious at best, I doubt
it is really testing what it thinks it is.
llvm-svn: 60068
2008-11-26 08:26:16 +08:00
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define i8 @test(i32 *%P) nounwind {
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%Q = getelementptr i32* %P, i32 1
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%R = bitcast i32* %Q to i8*
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%S = load i8* %R
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%T = icmp eq i8 %S, 0
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br i1 %T, label %TB, label %F
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TB:
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ret i8 4
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F:
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%U = getelementptr i8* %R, i32 3
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%V = load i8* %U
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ret i8 %V
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}
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