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65f612f852
This can prove that:
extern int f;
int g() {
int x = 0;
for (int i = 0; i < 365; ++i) {
x /= f;
}
return x;
}
always returns zero. Thanks to Sanjoy for confirming this
transformation actually made sense (bugs are mine).
llvm-svn: 292531
33 lines
699 B
LLVM
33 lines
699 B
LLVM
; RUN: opt < %s -sccp -S | FileCheck %s
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; Test that SCCP has basic knowledge of when div can nuke overdefined values.
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; 0 / X = 0 even if X is overdefined.
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; CHECK-LABEL: test1
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; CHECK-NEXT: ret i32 0
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define i32 @test1(i32 %foo) {
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%tinkywinky = udiv i32 0, %foo
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ret i32 %tinkywinky
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}
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; CHECK-LABEL: test2
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; CHECK-NEXT: ret i32 0
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define i32 @test2(i32 %foo) {
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%tinkywinky = sdiv i32 0, %foo
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ret i32 %tinkywinky
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}
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; CHECK-LABEL: test3
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; CHECK: ret i32 %tinkywinky
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define i32 @test3(i32 %foo) {
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%tinkywinky = udiv i32 %foo, 0
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ret i32 %tinkywinky
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}
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; CHECK-LABEL: test4
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; CHECK: ret i32 %tinkywinky
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define i32 @test4(i32 %foo) {
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%tinkywinky = sdiv i32 %foo, 0
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ret i32 %tinkywinky
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}
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