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It is not safe to sink an alloca into a stacksave/stackrestore pair, so don't do that. <rdar://problem/10352360>

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143093 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman 2011-10-27 01:33:51 +00:00
parent 6d64b3adab
commit 8ecde6cbf8
2 changed files with 40 additions and 14 deletions
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11
lib/Transforms/Scalar/IndVarSimplify.cpp
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@ -1680,11 +1680,12 @@ void IndVarSimplify::SinkUnusedInvariants(Loop *L) {
if (isa<LandingPadInst>(I))
continue;
// Don't sink static AllocaInsts out of the entry block, which would
// turn them into dynamic allocas!
if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
if (AI->isStaticAlloca())
continue;
// Don't sink alloca: we never want to sink static alloca's out of the
// entry block, and correctly sinking dynamic alloca's requires
// checks for stacksave/stackrestore intrinsics.
// FIXME: Refactor this check somehow?
if (isa<AllocaInst>(I))
continue;
// Determine if there is a use in or before the loop (direct or
// otherwise).

43
test/Transforms/IndVarSimplify/sink-alloca.ll
View File

@ -1,15 +1,10 @@
; RUN: opt < %s -indvars -S | FileCheck %s
; PR4775
; Indvars shouldn't sink the alloca out of the entry block, even though
; it's not used until after the loop.
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i386-apple-darwin10.0"
@llvm.used = appending global [1 x i8*] [i8* bitcast (i32 ()* @main to i8*)],
section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]
; PR4775
; Indvars shouldn't sink the alloca out of the entry block, even though
; it's not used until after the loop.
define i32 @main() nounwind {
; CHECK: entry:
; CHECK-NEXT: %result.i = alloca i32, align 4
@ -27,5 +22,35 @@ while.end: ; preds = %while.cond
%tmp.i = volatile load i32* %result.i ; <i32> [#uses=0]
ret i32 0
}
declare i32 @bar()
; <rdar://problem/10352360>
; Indvars shouldn't sink the first alloca between the stacksave and stackrestore
; intrinsics.
declare i8* @a(...)
declare i8* @llvm.stacksave() nounwind
declare void @llvm.stackrestore(i8*) nounwind
define void @h(i64 %n) nounwind uwtable ssp {
; CHECK: entry:
; CHECK-NEXT: %vla = alloca i8*
; CHECK-NEXT: %savedstack = call i8* @llvm.stacksave()
entry:
%vla = alloca i8*, i64 %n, align 16
%savedstack = call i8* @llvm.stacksave() nounwind
%vla.i = alloca i8*, i64 %n, align 16
br label %for.body.i
for.body.i:
%indvars.iv37.i = phi i64 [ %indvars.iv.next38.i, %for.body.i ], [ 0, %entry ]
%call.i = call i8* (...)* @a() nounwind
%arrayidx.i = getelementptr inbounds i8** %vla.i, i64 %indvars.iv37.i
store i8* %call.i, i8** %arrayidx.i, align 8
%indvars.iv.next38.i = add i64 %indvars.iv37.i, 1
%exitcond5 = icmp eq i64 %indvars.iv.next38.i, %n
br i1 %exitcond5, label %g.exit, label %for.body.i
g.exit:
call void @llvm.stackrestore(i8* %savedstack) nounwind
%call1 = call i8* (...)* @a(i8** %vla) nounwind
ret void
}