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[FIX] Use unreachable to indicate dead code and repair dominance 

When we bail out early we make the partially build new code path
  practically dead, though it was not unreachable. To remove dominance
  problems we now make it not only dead but also prevent the control
  flow to join with the original code path, thus allow to use original
  values after the SCoP without any PHI nodes.

This fixes bug 25447.

llvm-svn: 252420
This commit is contained in:
Johannes Doerfert 2015-11-08 17:57:41 +00:00
parent 1dd6e37af4
commit 3797707695
2 changed files with 55 additions and 1 deletions
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7
polly/lib/CodeGen/CodeGeneration.cpp
View File

@ -152,7 +152,12 @@ public:
if (!NodeBuilder.preloadInvariantLoads()) {
auto *FalseI1 = Builder.getFalse();
Builder.GetInsertBlock()->getTerminator()->setOperand(0, FalseI1);
auto *SplitBBTerm = Builder.GetInsertBlock()->getTerminator();
SplitBBTerm->setOperand(0, FalseI1);
auto *StartBBTerm = StartBlock->getTerminator();
Builder.SetInsertPoint(StartBBTerm);
Builder.CreateUnreachable();
StartBBTerm->eraseFromParent();
isl_ast_node_free(AstRoot);
} else {

49
polly/test/Isl/CodeGen/dominance_problem_after_early_codegen_bailout.ll Normal file
View File

@ -0,0 +1,49 @@
; RUN: opt %loadPolly -polly-codegen -analyze < %s
;
; This caused dominance problems at some point as we do bail out during
; code generation. Just verify it runs through.
;
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
%struct.hashheader.0.5.10.165.180.185 = type { i16, i16, i16, i16, i16, i16, i32, i32, i32, i32, i32, i32, i32, i32, i32, [5 x i8], [13 x i8], i8, i8, i8, [228 x i16], [228 x i8], [228 x i8], [228 x i8], [228 x i8], [228 x i8], [228 x i8], [128 x i8], [100 x [11 x i8]], [100 x i32], [100 x i32], i16 }
@hashheader = external global %struct.hashheader.0.5.10.165.180.185, align 4
; Function Attrs: nounwind uwtable
define void @strtoichar(i8* %in) #0 {
entry:
br i1 undef, label %land.rhs, label %for.end
land.rhs: ; preds = %for.inc, %entry
%in.addr.012 = phi i8* [ undef, %for.inc ], [ %in, %entry ]
%0 = load i8, i8* %in.addr.012, align 1
br i1 undef, label %for.end, label %for.body
for.body: ; preds = %land.rhs
%idxprom = zext i8 %0 to i64
%arrayidx = getelementptr inbounds %struct.hashheader.0.5.10.165.180.185, %struct.hashheader.0.5.10.165.180.185* @hashheader, i64 0, i32 27, i64 %idxprom
%1 = load i8, i8* %arrayidx, align 1
%tobool = icmp eq i8 %1, 0
br i1 %tobool, label %if.else, label %land.rhs.7
land.rhs.7: ; preds = %for.body
tail call void @stringcharlen()
br i1 undef, label %if.then, label %if.else
if.then: ; preds = %land.rhs.7
br label %for.inc
if.else: ; preds = %land.rhs.7, %for.body
%2 = load i8, i8* %in.addr.012, align 1
br label %for.inc
for.inc: ; preds = %if.else, %if.then
%len.1 = phi i32 [ 0, %if.else ], [ undef, %if.then ]
br i1 undef, label %land.rhs, label %for.end
for.end: ; preds = %for.inc, %land.rhs, %entry
ret void
}
; Function Attrs: nounwind uwtable
declare void @stringcharlen() #0