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https://github.com/c64scene-ar/llvm-6502.git
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e70da20f9a
_foo: movl $12, %eax andl 4(%esp), %eax movl _array(%eax), %eax ret instead of: _foo: movl 4(%esp), %eax shrl $2, %eax andl $3, %eax movl _array(,%eax,4), %eax ret As it turns out, this triggers all the time, in a wide variety of situations, for example, I see diffs like this in various programs: - movl 8(%eax), %eax - shll $2, %eax - andl $1020, %eax - movl (%esi,%eax), %eax + movzbl 8(%eax), %eax + movl (%esi,%eax,4), %eax - shll $2, %edx - andl $1020, %edx - movl (%edi,%edx), %edx + andl $255, %edx + movl (%edi,%edx,4), %edx Unfortunately, I also see stuff like this, which can be fixed in the X86 backend: - andl $85, %ebx - addl _bit_count(,%ebx,4), %ebp + shll $2, %ebx + andl $340, %ebx + addl _bit_count(%ebx), %ebp git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44656 91177308-0d34-0410-b5e6-96231b3b80d8
16 lines
567 B
LLVM
16 lines
567 B
LLVM
; RUN: llvm-as < %s | llc | not grep shrl
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target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
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target triple = "i686-apple-darwin8"
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@array = weak global [4 x i32] zeroinitializer ; <[4 x i32]*> [#uses=1]
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define i32 @foo(i32 %x) {
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entry:
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%tmp2 = lshr i32 %x, 2 ; <i32> [#uses=1]
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%tmp3 = and i32 %tmp2, 3 ; <i32> [#uses=1]
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%tmp4 = getelementptr [4 x i32]* @array, i32 0, i32 %tmp3 ; <i32*> [#uses=1]
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%tmp5 = load i32* %tmp4, align 4 ; <i32> [#uses=1]
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ret i32 %tmp5
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}
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