07005440ae
Loop Strength Reduce sometimes optimizes away all uses of an induction variable from a loop but leaves the IV increments. When the only remaining use of the IV is the PHI in the exit block, this patch will call rewriteLoopExitValues to replace the exit block PHI with the final value of the IV to skip the updates in each loop iteration. Differential Revision: https://reviews.llvm.org/D118808
58 lines
1.7 KiB
LLVM
58 lines
1.7 KiB
LLVM
; RUN: opt < %s -S -loop-reduce | FileCheck %s
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define void @testIVNext(i64* nocapture %a, i64 signext %m, i64 signext %n) {
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entry:
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br label %for.body
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for.body:
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%indvars.iv.prol = phi i64 [ %indvars.iv.next.prol, %for.body ], [ %m, %entry ]
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%i = phi i64 [ %i.next, %for.body ], [ 0, %entry ]
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%uglygep138 = getelementptr i64, i64* %a, i64 %i
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store i64 55, i64* %uglygep138, align 4
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%indvars.iv.next.prol = add nuw nsw i64 %indvars.iv.prol, 1
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%i.next = add i64 %i, 1
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%i.cmp.not = icmp eq i64 %i.next, %n
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br i1 %i.cmp.not, label %for.exit, label %for.body
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; CHECK: entry:
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; CHECK: %0 = add i64 %n, %m
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; CHECK-NOT : %indvars.iv.next.prol
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; CHECK-NOT: %indvars.iv.prol
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; CHECK: %indvars.iv.unr = phi i64 [ %0, %for.exit ]
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for.exit:
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%indvars.iv.next.prol.lcssa = phi i64 [ %indvars.iv.next.prol, %for.body ]
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br label %exit
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exit:
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%indvars.iv.unr = phi i64 [ %indvars.iv.next.prol.lcssa, %for.exit ]
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ret void
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}
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define void @testIV(i64* nocapture %a, i64 signext %m, i64 signext %n) {
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entry:
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br label %for.body
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for.body:
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%iv.prol = phi i64 [ %iv.next.prol, %for.body ], [ %m, %entry ]
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%i = phi i64 [ %i.next, %for.body ], [ 0, %entry ]
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%uglygep138 = getelementptr i64, i64* %a, i64 %i
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store i64 55, i64* %uglygep138, align 4
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%iv.next.prol = add nuw nsw i64 %iv.prol, 1
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%i.next = add i64 %i, 1
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%i.cmp.not = icmp eq i64 %i.next, %n
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br i1 %i.cmp.not, label %for.exit, label %for.body
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; CHECK: entry:
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; CHECK: %0 = add i64 %n, %m
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; CHECK: %1 = add i64 %0, -1
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; CHECK-NOT: %iv.next.prol
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; CHECK-NOT: %iv.prol
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; CHECK: %indvars.iv.unr = phi i64 [ %1, %for.exit ]
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for.exit:
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%iv.prol.lcssa = phi i64 [ %iv.prol, %for.body ]
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br label %exit
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exit:
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%indvars.iv.unr = phi i64 [%iv.prol.lcssa, %for.exit]
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ret void
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}
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