4739dd67e7
This is a resubmit of dd6bb367 (which was reverted due to stage2 build failures in 7c63aac), with the additional restriction added to the transform to only consider outer most loops. As shown in the added test case, ensuring LCSSA is up to date when deleting an inner loop is tricky as we may actually need to remove blocks from any outer loops, thus changing the exit block set. For the moment, just avoid transforming this case. I plan to return to this case in a follow up patch and see if we can do better. Original commit message follows... The basic idea is that if SCEV can prove the backedge isn't taken, we can go ahead and get rid of the backedge (and thus the loop) while leaving the rest of the control in place. This nicely handles cases with dispatch between multiple exits and internal side effects. Differential Revision: https://reviews.llvm.org/D93906
174 lines
7.9 KiB
LLVM
174 lines
7.9 KiB
LLVM
; RUN: opt -S -analyze -scalar-evolution -loop-deletion -scalar-evolution -verify-scev < %s -enable-new-pm=0 | FileCheck %s --check-prefix=SCEV-EXPRS
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; RUN: opt -S -passes='print<scalar-evolution>,loop-deletion,print<scalar-evolution>' -verify-scev < %s 2>&1 | FileCheck %s --check-prefix=SCEV-EXPRS
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; RUN: opt -S -loop-deletion < %s | FileCheck %s --check-prefix=IR-AFTER-TRANSFORM
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; RUN: opt -S -indvars -loop-deletion -indvars < %s | FileCheck %s --check-prefix=ORIGINAL-CRASH
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; Checking for a crash. Loop-deletion would change the loop
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; disposition of an instruction, but not update SCEV.
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx10.11.0"
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define void @pr27570() {
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; IR-AFTER-TRANSFORM-LABEL: @pr27570(
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; ORIGINAL-CRASH: @pr27570(
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entry:
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br label %for.cond
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for.cond: ; preds = %for.cond14, %entry
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%f.0 = phi i32 [ 20, %entry ], [ 0, %for.cond14 ]
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br label %for.body
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for.body: ; preds = %for.inc11, %for.cond
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; IR-AFTER-TRANSFORM: for.body:
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; IR-AFTER-TRANSFORM: %cmp = icmp eq i32 %val, -1
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; IR-AFTER-TRANSFORM: %conv7 = zext i1 %cmp to i32
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; IR-AFTER-TRANSFORM: for.body6:
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; SCEV-EXPRS: %conv7 = zext i1 %cmp to i32
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; SCEV-EXPRS: %conv7 = zext i1 %cmp to i32
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; SCEV-EXPRS-NEXT: --> {{.*}} LoopDispositions: { %for.body: Variant, %for.cond: Variant, %for.body6: Invariant }
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%val = phi i32 [ -20, %for.cond ], [ %inc12, %for.inc11 ]
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%g.040 = phi i32 [ -20, %for.cond ], [ %and.lcssa, %for.inc11 ]
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br label %for.body6
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for.body6: ; preds = %for.body6, %for.body
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%h.039 = phi i32 [ 1, %for.body ], [ %inc, %for.body6 ]
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%g.138 = phi i32 [ %g.040, %for.body ], [ %and, %for.body6 ]
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%cmp = icmp eq i32 %val, -1
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%conv7 = zext i1 %cmp to i32
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%add.i = add nsw i32 %conv7, %h.039
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%sext = shl i32 %add.i, 24
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%conv8 = ashr exact i32 %sext, 24
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%cmp9 = icmp eq i32 %conv8, %f.0
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%conv10 = zext i1 %cmp9 to i32
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%and = and i32 %conv10, %g.138
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%inc = add i32 %h.039, 1
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%exit = icmp eq i32 %inc, 20000
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br i1 %exit, label %for.inc11, label %for.body6
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for.inc11: ; preds = %for.body6
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%and.lcssa = phi i32 [ %and, %for.body6 ]
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call void @sideeffect(i32 %and.lcssa)
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%inc12 = add nsw i32 %val, 1
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%tobool = icmp eq i32 %inc12, 0
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br i1 %tobool, label %for.cond14, label %for.body
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for.cond14: ; preds = %for.cond14, %for.inc11
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br i1 undef, label %for.cond, label %for.cond14
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}
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declare void @sideeffect(i32)
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; LoopDeletion removes the loop %for.body7.1. Make sure %inc.lcssa.1 in the loop
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; exit block is correctly invalidated.
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define void @test2(double* %bx, i64 %by) local_unnamed_addr align 2 {
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; IR-AFTER-TRANSFORM-LABEL: @test2(
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; IR-AFTER-TRANSFORM-NOT: for.body7.1:
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; SCEV-EXPRS-LABEL: test2
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; SCEV-EXPRS: %inc.lcssa.1 = phi i64 [ undef, %for.body7.preheader.1 ]
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; SCEV-EXPRS-NEXT: --> undef
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entry:
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%cmp = icmp sgt i64 %by, 0
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br label %for.cond.preheader
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for.cond.preheader: ; preds = %entry
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br i1 %cmp, label %for.cond5.preheader.lr.ph, label %for.end14
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for.cond5.preheader.lr.ph: ; preds = %for.cond.preheader
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br label %for.cond5.preheader
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for.cond.loopexit.loopexit: ; preds = %for.body10
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%inc11.lcssa = phi i64 [ %inc11, %for.body10 ]
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br label %for.cond.loopexit
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for.cond.loopexit: ; preds = %for.cond8.preheader, %for.cond.loopexit.loopexit
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%ca.3.lcssa = phi i64 [ %ca.2.lcssa, %for.cond8.preheader ], [ %inc11.lcssa, %for.cond.loopexit.loopexit ]
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br i1 %cmp, label %for.cond5.preheader, label %for.end14.loopexit
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for.cond5.preheader: ; preds = %for.cond.loopexit, %for.cond5.preheader.lr.ph
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%ca.19 = phi i64 [ 0, %for.cond5.preheader.lr.ph ], [ %ca.3.lcssa, %for.cond.loopexit ]
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br i1 false, label %for.cond8.preheader, label %for.body7.preheader
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for.body7.preheader: ; preds = %for.cond5.preheader
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br label %for.body7
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for.cond8.preheader.loopexit: ; preds = %for.body7
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%inc.lcssa = phi i64 [ %inc, %for.body7 ]
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br label %for.cond8.preheader
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for.cond8.preheader: ; preds = %for.cond8.preheader.loopexit, %for.cond5.preheader
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%ca.2.lcssa = phi i64 [ %ca.19, %for.cond5.preheader ], [ %inc.lcssa, %for.cond8.preheader.loopexit ]
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br i1 true, label %for.body10.preheader, label %for.cond.loopexit
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for.body10.preheader: ; preds = %for.cond8.preheader
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br label %for.body10
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for.body7: ; preds = %for.body7, %for.body7.preheader
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%ca.26 = phi i64 [ %inc, %for.body7 ], [ %ca.19, %for.body7.preheader ]
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%inc = add nsw i64 %ca.26, 1
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%arrayidx = getelementptr inbounds double, double* %bx, i64 %ca.26
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store double 0.000000e+00, double* %arrayidx, align 8
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br i1 false, label %for.cond8.preheader.loopexit, label %for.body7
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for.body10: ; preds = %for.body10, %for.body10.preheader
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%ca.37 = phi i64 [ %inc11, %for.body10 ], [ %ca.2.lcssa, %for.body10.preheader ]
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%inc11 = add nsw i64 %ca.37, 1
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br i1 true, label %for.body10, label %for.cond.loopexit.loopexit
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for.end14.loopexit: ; preds = %for.cond.loopexit
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br label %for.end14
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for.end14: ; preds = %for.end14.loopexit, %for.cond.preheader
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br i1 %cmp, label %for.cond5.preheader.lr.ph.1, label %for.end14.1
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for.cond5.preheader.lr.ph.1: ; preds = %for.end14
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br label %for.cond5.preheader.1
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for.cond5.preheader.1: ; preds = %for.cond.loopexit.1, %for.cond5.preheader.lr.ph.1
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%ca.19.1 = phi i64 [ 0, %for.cond5.preheader.lr.ph.1 ], [ %ca.3.lcssa.1, %for.cond.loopexit.1 ]
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br i1 true, label %for.cond8.preheader.1, label %for.body7.preheader.1
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for.body7.preheader.1: ; preds = %for.cond5.preheader.1
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br label %for.body7.1
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for.body7.1: ; preds = %for.body7.1, %for.body7.preheader.1
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%ca.26.1 = phi i64 [ %inc.1, %for.body7.1 ], [ %ca.19.1, %for.body7.preheader.1 ]
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%inc.1 = add nsw i64 %ca.26.1, 1
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%arrayidx.1 = getelementptr inbounds double, double* %bx, i64 %ca.26.1
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store double 0.000000e+00, double* %arrayidx.1, align 8
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br i1 true, label %for.cond8.preheader.loopexit.1, label %for.body7.1
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for.cond8.preheader.loopexit.1: ; preds = %for.body7.1
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%inc.lcssa.1 = phi i64 [ %inc.1, %for.body7.1 ]
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br label %for.cond8.preheader.1
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for.cond8.preheader.1: ; preds = %for.cond8.preheader.loopexit.1, %for.cond5.preheader.1
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%ca.2.lcssa.1 = phi i64 [ %ca.19.1, %for.cond5.preheader.1 ], [ %inc.lcssa.1, %for.cond8.preheader.loopexit.1 ]
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br i1 false, label %for.body10.preheader.1, label %for.cond.loopexit.1
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for.body10.preheader.1: ; preds = %for.cond8.preheader.1
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br label %for.body10.1
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for.body10.1: ; preds = %for.body10.1, %for.body10.preheader.1
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%ca.37.1 = phi i64 [ %inc11.1, %for.body10.1 ], [ %ca.2.lcssa.1, %for.body10.preheader.1 ]
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%inc11.1 = add nsw i64 %ca.37.1, 1
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br i1 false, label %for.body10.1, label %for.cond.loopexit.loopexit.1
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for.cond.loopexit.loopexit.1: ; preds = %for.body10.1
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%inc11.lcssa.1 = phi i64 [ %inc11.1, %for.body10.1 ]
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br label %for.cond.loopexit.1
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for.cond.loopexit.1: ; preds = %for.cond.loopexit.loopexit.1, %for.cond8.preheader.1
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%ca.3.lcssa.1 = phi i64 [ %ca.2.lcssa.1, %for.cond8.preheader.1 ], [ %inc11.lcssa.1, %for.cond.loopexit.loopexit.1 ]
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br i1 %cmp, label %for.cond5.preheader.1, label %for.end14.loopexit.1
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for.end14.loopexit.1: ; preds = %for.cond.loopexit.1
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br label %for.end14.1
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for.end14.1: ; preds = %for.end14.loopexit.1, %for.end14
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ret void
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}
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