mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-28 04:29:44 +00:00
8c06aa1c59
We could implement a DAGCombine to turn x * 0x0101 back into logic operations
on targets that doesn't support the multiply or it is slow (p4) if someone cares
enough.
Example code:
void test(char *s, int a) {
__builtin_memset(s, a, 4);
}
before:
_test: ## @test
movzbl 8(%esp), %eax
movl %eax, %ecx
shll $8, %ecx
orl %eax, %ecx
movl %ecx, %eax
shll $16, %eax
orl %ecx, %eax
movl 4(%esp), %ecx
movl %eax, 4(%ecx)
movl %eax, (%ecx)
ret
after:
_test: ## @test
movzbl 8(%esp), %eax
imull $16843009, %eax, %eax ## imm = 0x1010101
movl 4(%esp), %ecx
movl %eax, 4(%ecx)
movl %eax, (%ecx)
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122707 91177308-0d34-0410-b5e6-96231b3b80d8
31 lines
735 B
LLVM
31 lines
735 B
LLVM
; RUN: llc -mtriple=i386-apple-darwin < %s | FileCheck %s
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declare void @llvm.memset.i32(i8*, i8, i32, i32) nounwind
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define fastcc void @t1() nounwind {
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entry:
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; CHECK: t1:
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; CHECK: calll _memset
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call void @llvm.memset.i32( i8* null, i8 0, i32 188, i32 1 ) nounwind
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unreachable
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}
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define fastcc void @t2(i8 signext %c) nounwind {
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entry:
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; CHECK: t2:
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; CHECK: calll _memset
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call void @llvm.memset.i32( i8* undef, i8 %c, i32 76, i32 1 ) nounwind
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unreachable
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}
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declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind
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define void @t3(i8* nocapture %s, i8 %a) nounwind {
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entry:
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tail call void @llvm.memset.p0i8.i32(i8* %s, i8 %a, i32 8, i32 1, i1 false)
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ret void
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; CHECK: t3:
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; CHECK: imull $16843009
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}
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