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https://github.com/c64scene-ar/llvm-6502.git
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5d59315f13
Summary: Because LSR happens at a late stage where mul of a power of 2 is typically canonicalized to shl, this canonicalization emits code that can be better CSE'ed. Test Plan: Transforms/LoopStrengthReduce/shl.ll shows how this change makes GVN more powerful. Fixes some existing tests due to this change. Reviewers: sanjoy, majnemer, atrick Reviewed By: majnemer, atrick Subscribers: majnemer, llvm-commits Differential Revision: http://reviews.llvm.org/D10448 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240573 91177308-0d34-0410-b5e6-96231b3b80d8
39 lines
1.3 KiB
LLVM
39 lines
1.3 KiB
LLVM
; RUN: opt < %s -loop-reduce -gvn -S | FileCheck %s
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target datalayout = "e-i64:64-v16:16-v32:32-n16:32:64"
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define void @_Z3fooPfll(float* nocapture readonly %input, i64 %n, i64 %s) {
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; CHECK-LABEL: @_Z3fooPfll(
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entry:
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%mul = shl nsw i64 %s, 2
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; CHECK: %mul = shl i64 %s, 2
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tail call void @_Z3bazl(i64 %mul) #2
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; CHECK-NEXT: call void @_Z3bazl(i64 %mul)
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%cmp.5 = icmp sgt i64 %n, 0
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br i1 %cmp.5, label %for.body.preheader, label %for.cond.cleanup
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for.body.preheader: ; preds = %entry
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br label %for.body
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for.cond.cleanup.loopexit: ; preds = %for.body
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br label %for.cond.cleanup
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for.cond.cleanup: ; preds = %for.cond.cleanup.loopexit, %entry
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ret void
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for.body: ; preds = %for.body.preheader, %for.body
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%i.06 = phi i64 [ %add, %for.body ], [ 0, %for.body.preheader ]
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%arrayidx = getelementptr inbounds float, float* %input, i64 %i.06
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; LoopStrengthReduce should reuse %mul as the stride.
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; CHECK: getelementptr i1, i1* {{[^,]+}}, i64 %mul
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%0 = load float, float* %arrayidx, align 4
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tail call void @_Z3barf(float %0) #2
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%add = add nsw i64 %i.06, %s
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%cmp = icmp slt i64 %add, %n
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br i1 %cmp, label %for.body, label %for.cond.cleanup.loopexit
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}
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declare void @_Z3bazl(i64)
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declare void @_Z3barf(float)
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