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075fb5d68f
references. For example, this allows gvn to eliminate the load in
this example:
void foo(int n, int* p, int *q) {
p[0] = 0;
p[1] = 1;
if (n) {
*q = p[0];
}
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118714 91177308-0d34-0410-b5e6-96231b3b80d8
60 lines
1.3 KiB
LLVM
60 lines
1.3 KiB
LLVM
; RUN: opt -basicaa -gvn -S < %s | FileCheck %s
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target datalayout = "e-p:64:64:64"
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; GVN should ignore the store to p[1] to see that the load from p[0] is
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; fully redundant.
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; CHECK: @yes
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; CHECK: if.then:
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; CHECK-NEXT: store i32 0, i32* %q
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; CHECK-NEXT: ret void
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define void @yes(i1 %c, i32* %p, i32* %q) nounwind {
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entry:
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store i32 0, i32* %p
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%p1 = getelementptr inbounds i32* %p, i64 1
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store i32 1, i32* %p1
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br i1 %c, label %if.else, label %if.then
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if.then:
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%t = load i32* %p
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store i32 %t, i32* %q
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ret void
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if.else:
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ret void
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}
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; GVN should ignore the store to p[1] to see that the first load from p[0] is
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; fully redundant. However, the second load is larger, so it's not a simple
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; redundancy.
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; CHECK: @watch_out_for_size_change
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; CHECK: if.then:
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; CHECK-NEXT: store i32 0, i32* %q
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; CHECK-NEXT: ret void
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; CHECK: if.else:
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; CHECK: load i64* %pc
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; CHECK: store i64
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define void @watch_out_for_size_change(i1 %c, i32* %p, i32* %q) nounwind {
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entry:
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store i32 0, i32* %p
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%p1 = getelementptr inbounds i32* %p, i64 1
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store i32 1, i32* %p1
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br i1 %c, label %if.else, label %if.then
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if.then:
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%t = load i32* %p
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store i32 %t, i32* %q
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ret void
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if.else:
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%pc = bitcast i32* %p to i64*
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%qc = bitcast i32* %q to i64*
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%t64 = load i64* %pc
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store i64 %t64, i64* %qc
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ret void
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}
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