[llvm] r291966 - [LoopStrengthReduce] Don't bother rewriting PHIs in catchswitch blocks

[David Majnemer via llvm-commits]

I think so.

On Fri, Jan 13, 2017 at 3:59 PM, Hans Wennborg <hans at chromium.org> wrote:

> Should we merge this to the release branch?
>
> On Fri, Jan 13, 2017 at 2:24 PM, David Majnemer via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> > Author: majnemer
> > Date: Fri Jan 13 16:24:27 2017
> > New Revision: 291966
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=291966&view=rev
> > Log:
> > [LoopStrengthReduce] Don't bother rewriting PHIs in catchswitch blocks
> >
> > The catchswitch instruction cannot be split, don't bother trying to
> > rewrite it.
> >
> > This fixes PR31627.
> >
> > Added:
> >     llvm/trunk/test/Transforms/LoopStrengthReduce/pr31627.ll
> > Modified:
> >     llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
> >
> > Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> Transforms/Scalar/LoopStrengthReduce.cpp?rev=291966&r1=291965&r2=291966&
> view=diff
> > ============================================================
> ==================
> > --- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Fri Jan 13
> 16:24:27 2017
> > @@ -3163,6 +3163,9 @@ LSRInstance::CollectLoopInvariantFixupsA
> >          // Don't bother if the instruction is in a BB which ends in an
> EHPad.
> >          if (UseBB->getTerminator()->isEHPad())
> >            continue;
> > +        // Don't bother rewriting PHIs in catchswitch blocks.
> > +        if (isa<CatchSwitchInst>(UserInst->getParent()->
> getTerminator()))
> > +          continue;
> >          // Ignore uses which are part of other SCEV expressions, to
> avoid
> >          // analyzing them multiple times.
> >          if (SE.isSCEVable(UserInst->getType())) {
> > @@ -4672,7 +4675,8 @@ void LSRInstance::RewriteForPHI(PHINode
> >        // is the canonical backedge for this loop, which complicates
> post-inc
> >        // users.
> >        if (e != 1 && BB->getTerminator()->getNumSuccessors() > 1 &&
> > -          !isa<IndirectBrInst>(BB->getTerminator())) {
> > +          !isa<IndirectBrInst>(BB->getTerminator()) &&
> > +          !isa<CatchSwitchInst>(BB->getTerminator())) {
> >          BasicBlock *Parent = PN->getParent();
> >          Loop *PNLoop = LI.getLoopFor(Parent);
> >          if (!PNLoop || Parent != PNLoop->getHeader()) {
> >
> > Added: llvm/trunk/test/Transforms/LoopStrengthReduce/pr31627.ll
> > URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> Transforms/LoopStrengthReduce/pr31627.ll?rev=291966&view=auto
> > ============================================================
> ==================
> > --- llvm/trunk/test/Transforms/LoopStrengthReduce/pr31627.ll (added)
> > +++ llvm/trunk/test/Transforms/LoopStrengthReduce/pr31627.ll Fri Jan 13
> 16:24:27 2017
> > @@ -0,0 +1,58 @@
> > +; RUN: opt -S -loop-reduce < %s | FileCheck %s
> > +target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
> > +target triple = "x86_64-pc-windows-msvc19.0.24215"
> > +
> > +define void @fn3() personality i32 (...)* @__CxxFrameHandler3 {
> > +entry:
> > +  %call = invoke i32 @fn2()
> > +          to label %for.cond.preheader unwind label %catch.dispatch2
> > +
> > +for.cond.preheader:                               ; preds = %entry
> > +  br label %for.cond
> > +
> > +for.cond:                                         ; preds =
> %for.cond.preheader, %for.cond
> > +  %b.0 = phi i32 [ %inc, %for.cond ], [ %call, %for.cond.preheader ]
> > +  %inc = add nsw i32 %b.0, 1
> > +  invoke void @fn1(i32 %inc)
> > +          to label %for.cond unwind label %catch.dispatch
> > +
> > +; CHECK:   %[[add:.*]] = add i32 %call, 1
> > +; CHECK:   br label %for.cond
> > +
> > +; CHECK: for.cond:                                         ; preds =
> %for.cond, %for.cond.preheader
> > +; CHECK:   %[[lsr_iv:.*]] = phi i32 [ %lsr.iv.next, %for.cond ], [
> %[[add]], %for.cond.preheader ]
> > +; CHECK:   %[[lsr_iv_next:.*]] = add i32 %lsr.iv, 1
> > +; CHECK:   invoke void @fn1(i32 %[[lsr_iv]])
> > +
> > +
> > +catch.dispatch:                                   ; preds = %for.cond
> > +  %0 = catchswitch within none [label %catch] unwind label
> %catch.dispatch2
> > +
> > +catch:                                            ; preds =
> %catch.dispatch
> > +  %1 = catchpad within %0 [i8* null, i32 64, i8* null]
> > +  invoke void @_CxxThrowException(i8* null, i8* null) #2 [
> "funclet"(token %1) ]
> > +          to label %unreachable unwind label %catch.dispatch2
> > +
> > +catch.dispatch2:                                  ; preds =
> %catch.dispatch, %catch, %entry
> > +  %a.0 = phi i32 [ undef, %entry ], [ %call, %catch ], [ %call,
> %catch.dispatch ]
> > +  %2 = catchswitch within none [label %catch3] unwind to caller
> > +
> > +catch3:                                           ; preds =
> %catch.dispatch2
> > +  %3 = catchpad within %2 [i8* null, i32 64, i8* null]
> > +  call void @fn1(i32 %a.0) [ "funclet"(token %3) ]
> > +  catchret from %3 to label %try.cont4
> > +
> > +try.cont4:                                        ; preds = %catch3
> > +  ret void
> > +
> > +unreachable:                                      ; preds = %catch
> > +  unreachable
> > +}
> > +
> > +declare i32 @fn2()
> > +
> > +declare i32 @__CxxFrameHandler3(...)
> > +
> > +declare void @fn1(i32)
> > +
> > +declare void @_CxxThrowException(i8*, i8*)
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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