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https://github.com/c64scene-ar/llvm-6502.git
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30d8f0e977
The library call simplifier folds memcmp calls with all constant arguments
to a constant. For example:
memcmp("foo", "foo", 3) -> 0
memcmp("hel", "foo", 3) -> 1
memcmp("foo", "hel", 3) -> -1
The folding is implemented in terms of the system memcmp that LLVM gets
linked with. It currently just blindly uses the value returned from
the system memcmp as the folded constant.
This patch normalizes the values returned from the system memcmp to
(-1, 0, 1) so that we get consistent results across multiple platforms.
The test cases were adjusted accordingly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167726 91177308-0d34-0410-b5e6-96231b3b80d8
73 lines
2.1 KiB
LLVM
73 lines
2.1 KiB
LLVM
; Test that the memcmp library call simplifier works correctly.
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;
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; RUN: opt < %s -instcombine -S | FileCheck %s
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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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@foo = constant [4 x i8] c"foo\00"
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@hel = constant [4 x i8] c"hel\00"
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@hello_u = constant [8 x i8] c"hello_u\00"
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declare i32 @memcmp(i8*, i8*, i32)
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; Check memcmp(mem, mem, size) -> 0.
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define i32 @test_simplify1(i8* %mem, i32 %size) {
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; CHECK: @test_simplify1
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%ret = call i32 @memcmp(i8* %mem, i8* %mem, i32 %size)
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ret i32 %ret
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; CHECK: ret i32 0
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}
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; Check memcmp(mem1, mem2, 0) -> 0.
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define i32 @test_simplify2(i8* %mem1, i8* %mem2) {
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; CHECK: @test_simplify2
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%ret = call i32 @memcmp(i8* %mem1, i8* %mem2, i32 0)
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ret i32 %ret
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; CHECK: ret i32 0
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}
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;; Check memcmp(mem1, mem2, 1) -> *(unsigned char*)mem1 - *(unsigned char*)mem2.
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define i32 @test_simplify3(i8* %mem1, i8* %mem2) {
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; CHECK: @test_simplify3
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%ret = call i32 @memcmp(i8* %mem1, i8* %mem2, i32 1)
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; CHECK: [[LOAD1:%[a-z]+]] = load i8* %mem1, align 1
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; CHECK: [[ZEXT1:%[a-z]+]] = zext i8 [[LOAD1]] to i32
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; CHECK: [[LOAD2:%[a-z]+]] = load i8* %mem2, align 1
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; CHECK: [[ZEXT2:%[a-z]+]] = zext i8 [[LOAD2]] to i32
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; CHECK: [[RET:%[a-z]+]] = sub i32 [[ZEXT1]], [[ZEXT2]]
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ret i32 %ret
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; CHECK: ret i32 [[RET]]
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}
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; Check memcmp(mem1, mem2, size) -> cnst, where all arguments are constants.
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define i32 @test_simplify4() {
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; CHECK: @test_simplify4
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%mem1 = getelementptr [4 x i8]* @hel, i32 0, i32 0
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%mem2 = getelementptr [8 x i8]* @hello_u, i32 0, i32 0
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%ret = call i32 @memcmp(i8* %mem1, i8* %mem2, i32 3)
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ret i32 %ret
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; CHECK: ret i32 0
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}
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define i32 @test_simplify5() {
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; CHECK: @test_simplify5
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%mem1 = getelementptr [4 x i8]* @hel, i32 0, i32 0
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%mem2 = getelementptr [4 x i8]* @foo, i32 0, i32 0
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%ret = call i32 @memcmp(i8* %mem1, i8* %mem2, i32 3)
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ret i32 %ret
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; CHECK: ret i32 1
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}
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define i32 @test_simplify6() {
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; CHECK: @test_simplify6
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%mem1 = getelementptr [4 x i8]* @foo, i32 0, i32 0
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%mem2 = getelementptr [4 x i8]* @hel, i32 0, i32 0
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%ret = call i32 @memcmp(i8* %mem1, i8* %mem2, i32 3)
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ret i32 %ret
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; CHECK: ret i32 -1
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}
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