forked from OSchip/llvm-project
77 lines
2.4 KiB
LLVM
77 lines
2.4 KiB
LLVM
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; RUN: opt -basicaa -loop-load-elim -S < %s | FileCheck %s
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; When optimizing for size don't eliminate in this loop because the loop would
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; have to be versioned first because A and C may alias.
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;
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; for (unsigned i = 0; i < 100; i++) {
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; A[i+1] = B[i] + 2;
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; C[i] = A[i] * 2;
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; }
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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; CHECK-LABEL: @f(
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define void @f(i32* %A, i32* %B, i32* %C, i64 %N) optsize {
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%Aidx_next = getelementptr inbounds i32, i32* %A, i64 %indvars.iv.next
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%Bidx = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
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%Cidx = getelementptr inbounds i32, i32* %C, i64 %indvars.iv
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%Aidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
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%b = load i32, i32* %Bidx, align 4
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%a_p1 = add i32 %b, 2
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store i32 %a_p1, i32* %Aidx_next, align 4
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%a = load i32, i32* %Aidx, align 4
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; CHECK: %c = mul i32 %a, 2
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%c = mul i32 %a, 2
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store i32 %c, i32* %Cidx, align 4
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%exitcond = icmp eq i64 %indvars.iv.next, %N
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.body
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ret void
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}
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; Same loop but with noalias on %A and %C. In this case load-eliminate even
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; with -Os.
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; CHECK-LABEL: @g(
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define void @g(i32* noalias %A, i32* %B, i32* noalias %C, i64 %N) optsize {
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entry:
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%Aidx_next = getelementptr inbounds i32, i32* %A, i64 %indvars.iv.next
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%Bidx = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
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%Cidx = getelementptr inbounds i32, i32* %C, i64 %indvars.iv
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%Aidx = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
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%b = load i32, i32* %Bidx, align 4
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%a_p1 = add i32 %b, 2
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store i32 %a_p1, i32* %Aidx_next, align 4
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%a = load i32, i32* %Aidx, align 4
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; CHECK: %c = mul i32 %store_forwarded, 2
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%c = mul i32 %a, 2
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store i32 %c, i32* %Cidx, align 4
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%exitcond = icmp eq i64 %indvars.iv.next, %N
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.body
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ret void
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}
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