[llvm] r219899 - TRE: make TRE a bit more aggressive
Nick Lewycky
nlewycky at google.com
Fri Oct 17 12:56:38 PDT 2014
On 17 October 2014 12:17, Rafael Espíndola <rafael.espindola at gmail.com>
wrote:
> In fact this was PR7272.
>
PR7272 is the other way around?
define void @foo(i32* %x) {
tail call void @bar(i32* byval %x) ;; bad tail from PR7272
ret void
}
define void @foo(i32* byval %x) {
tail call void @bar(i32* %x) ;; okay tail from this patch
ret void
}
At least I think so?
On 17 October 2014 15:14, Rafael Espíndola <rafael.espindola at gmail.com>
> wrote:
> > Is this actually safe?
> >
> > The caller will deallocate the stack and then pass a pointer to that
> > area to the callee...
> >
> > On 15 October 2014 23:27, Saleem Abdulrasool <compnerd at compnerd.org>
> wrote:
> >> Author: compnerd
> >> Date: Wed Oct 15 22:27:30 2014
> >> New Revision: 219899
> >>
> >> URL: http://llvm.org/viewvc/llvm-project?rev=219899&view=rev
> >> Log:
> >> TRE: make TRE a bit more aggressive
> >>
> >> Make tail recursion elimination a bit more aggressive. This allows us
> to get
> >> tail recursion on functions that are just branches to a different
> function. The
> >> fact that the function takes a byval argument does not restrict it from
> being
> >> optimised into just a tail call.
> >>
> >> Added:
> >> llvm/trunk/test/Transforms/TailCallElim/byval.ll
> >> Modified:
> >> llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp
> >> llvm/trunk/test/Transforms/Inline/byval-tail-call.ll
> >> llvm/trunk/test/Transforms/TailCallElim/basic.ll
> >>
> >> Modified: llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp
> >> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp?rev=219899&r1=219898&r2=219899&view=diff
> >>
> ==============================================================================
> >> --- llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp
> (original)
> >> +++ llvm/trunk/lib/Transforms/Scalar/TailRecursionElimination.cpp Wed
> Oct 15 22:27:30 2014
> >> @@ -249,12 +249,7 @@ bool TailCallElim::markTails(Function &F
> >> return false;
> >> AllCallsAreTailCalls = true;
> >>
> >> - // The local stack holds all alloca instructions and all byval
> arguments.
> >> AllocaDerivedValueTracker Tracker;
> >> - for (Argument &Arg : F.args()) {
> >> - if (Arg.hasByValAttr())
> >> - Tracker.walk(&Arg);
> >> - }
> >> for (auto &BB : F) {
> >> for (auto &I : BB)
> >> if (AllocaInst *AI = dyn_cast<AllocaInst>(&I))
> >> @@ -310,9 +305,8 @@ bool TailCallElim::markTails(Function &F
> >> for (auto &Arg : CI->arg_operands()) {
> >> if (isa<Constant>(Arg.getUser()))
> >> continue;
> >> - if (Argument *A = dyn_cast<Argument>(Arg.getUser()))
> >> - if (!A->hasByValAttr())
> >> - continue;
> >> + if (isa<Argument>(Arg.getUser()))
> >> + continue;
> >> SafeToTail = false;
> >> break;
> >> }
> >>
> >> Modified: llvm/trunk/test/Transforms/Inline/byval-tail-call.ll
> >> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/byval-tail-call.ll?rev=219899&r1=219898&r2=219899&view=diff
> >>
> ==============================================================================
> >> --- llvm/trunk/test/Transforms/Inline/byval-tail-call.ll (original)
> >> +++ llvm/trunk/test/Transforms/Inline/byval-tail-call.ll Wed Oct 15
> 22:27:30 2014
> >> @@ -27,10 +27,11 @@ define internal void @qux(i32* byval %x)
> >> tail call void @ext(i32* null)
> >> ret void
> >> }
> >> +
> >> define void @frob(i32* %x) {
> >> ; CHECK-LABEL: define void @frob(
> >> ; CHECK: alloca i32
> >> -; CHECK: {{^ *}}call void @ext(
> >> +; CHECK: {{^ *}}tail call void @ext(
> >> ; CHECK: tail call void @ext(i32* null)
> >> ; CHECK: ret void
> >> tail call void @qux(i32* byval %x)
> >>
> >> Modified: llvm/trunk/test/Transforms/TailCallElim/basic.ll
> >> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/TailCallElim/basic.ll?rev=219899&r1=219898&r2=219899&view=diff
> >>
> ==============================================================================
> >> --- llvm/trunk/test/Transforms/TailCallElim/basic.ll (original)
> >> +++ llvm/trunk/test/Transforms/TailCallElim/basic.ll Wed Oct 15
> 22:27:30 2014
> >> @@ -147,7 +147,7 @@ cond_false:
> >> ; Don't tail call if a byval arg is captured.
> >> define void @test9(i32* byval %a) {
> >> ; CHECK-LABEL: define void @test9(
> >> -; CHECK: {{^ *}}call void @use(
> >> +; CHECK: {{^ *}}tail call void @use(
> >> call void @use(i32* %a)
> >> ret void
> >> }
> >>
> >> Added: llvm/trunk/test/Transforms/TailCallElim/byval.ll
> >> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/TailCallElim/byval.ll?rev=219899&view=auto
> >>
> ==============================================================================
> >> --- llvm/trunk/test/Transforms/TailCallElim/byval.ll (added)
> >> +++ llvm/trunk/test/Transforms/TailCallElim/byval.ll Wed Oct 15
> 22:27:30 2014
> >> @@ -0,0 +1,34 @@
> >> +; RUN: opt -mtriple i386 -Os -S %s -o - | FileCheck %s
> >> +; RUN: opt -mtriple x86_64 -Os -S %s -o - | FileCheck %s
> >> +; RUN: opt -mtriple armv7 -Os -S %s -o - | FileCheck %s
> >> +
> >> +%struct.D16 = type { [16 x double] }
> >> +
> >> +declare void @_Z2OpP3D16PKS_S2_(%struct.D16*, %struct.D16*,
> %struct.D16*)
> >> +
> >> +define void @_Z7TestRefRK3D16S1_(%struct.D16* noalias sret
> %agg.result, %struct.D16* %RHS, %struct.D16* %LHS) {
> >> + %1 = alloca %struct.D16*, align 8
> >> + %2 = alloca %struct.D16*, align 8
> >> + store %struct.D16* %RHS, %struct.D16** %1, align 8
> >> + store %struct.D16* %LHS, %struct.D16** %2, align 8
> >> + %3 = load %struct.D16** %1, align 8
> >> + %4 = load %struct.D16** %2, align 8
> >> + call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result, %struct.D16*
> %3, %struct.D16* %4)
> >> + ret void
> >> +}
> >> +
> >> +; CHECK: define void @_Z7TestRefRK3D16S1_({{.*}}) {
> >> +; CHECK: tail call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result,
> %struct.D16* %RHS, %struct.D16* %LHS)
> >> +; CHECK: ret void
> >> +; CHECK: }
> >> +
> >> +define void @_Z7TestVal3D16S_(%struct.D16* noalias sret %agg.result,
> %struct.D16* byval align 8 %RHS, %struct.D16* byval align 8 %LHS) {
> >> + call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result, %struct.D16*
> %RHS, %struct.D16* %LHS)
> >> + ret void
> >> +}
> >> +
> >> +; CHECK: define void @_Z7TestVal3D16S_({{.*}}) {
> >> +; CHECK: tail call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result,
> %struct.D16* %RHS, %struct.D16* %LHS)
> >> +; CHECK: ret void
> >> +; CHECK: }
> >> +
> >>
> >>
> >> _______________________________________________
> >> llvm-commits mailing list
> >> llvm-commits at cs.uiuc.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20141017/5c5fdfba/attachment.html>
More information about the llvm-commits
mailing list