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37eb422f69
This pass eliminates loop iterations that compute results that are not used later on. This can help e.g. in D, where the default zero-initialization is often unnecessary if right after new values are assigned to an array. Contributed-by: Peter Conn <conn.peter@gmail.com> llvm-svn: 201817
58 lines
1.8 KiB
LLVM
58 lines
1.8 KiB
LLVM
; RUN: opt -S %loadPolly -basicaa -polly-dependences-analysis-type=value-based -polly-dce -polly-ast -analyze < %s | FileCheck %s -check-prefix=CHECK-DCE
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
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target triple = "x86_64-pc-linux-gnu"
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; A[0] = 1;
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;
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; for(i = 0; i < 100; i++ )
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; A[i+1] = A[i] * 2;
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;
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; for (i = 0; i < 200; i++ )
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; A[i] = B[i] * 2;
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define void @main() nounwind uwtable {
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entry:
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%A = alloca [200 x i32], align 16
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%B = alloca [200 x i32], align 16
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%A.zero = getelementptr [200 x i32]* %A, i64 0, i64 0
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store i32 1, i32* %A.zero, align 4
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br label %for.body.1
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for.body.1:
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%indvar.1 = phi i64 [ 0, %entry ], [ %indvar.next.1, %for.body.1 ]
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%indvar.next.1 = add i64 %indvar.1, 1
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%A.current.1 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.1
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%val1.1 = load i32* %A.current.1, align 4
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%val2.1 = mul i32 %val1.1, 2
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%A.next.1 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.next.1
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store i32 %val2.1, i32* %A.next.1, align 4
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%exitcond.1 = icmp ne i64 %indvar.next.1, 100
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br i1 %exitcond.1, label %for.body.1, label %exit.1
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exit.1:
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br label %for.body.2
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for.body.2:
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%indvar.2 = phi i64 [ 0, %exit.1 ], [ %indvar.next.2, %for.body.2 ]
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%B.current.2 = getelementptr [200 x i32]* %B, i64 0, i64 %indvar.2
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%val1.2 = load i32* %B.current.2, align 4
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%val2.2 = mul i32 %val1.2, 2
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%A.current.2 = getelementptr [200 x i32]* %A, i64 0, i64 %indvar.2
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store i32 %val2.2, i32* %A.current.2, align 4
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%indvar.next.2 = add i64 %indvar.2, 1
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%exitcond.2 = icmp ne i64 %indvar.next.2, 200
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br i1 %exitcond.2, label %for.body.2, label %exit.3
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exit.3:
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ret void
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}
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; CHECK-DCE: for (int c1 = 0; c1 <= 199; c1 += 1)
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; CHECK-DCE: Stmt_for_body_2(c1);
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