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make sure to set Changed=true when instcombine hacks on the code, 

not doing so prevents it from properly iterating and prevents it
from deleting the entire body of dce-iterate.ll

llvm-svn: 63476
This commit is contained in:
Chris Lattner 2009-01-31 07:04:22 +00:00
parent b6080cf943
commit 94cfb281c3
2 changed files with 33 additions and 5 deletions
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14
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -12356,6 +12356,7 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
if (!I->use_empty())
I->replaceAllUsesWith(UndefValue::get(I->getType()));
I->eraseFromParent();
Changed = true;
}
}
}
@ -12375,6 +12376,7 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
I->eraseFromParent();
RemoveFromWorkList(I);
Changed = true;
continue;
}
@ -12389,17 +12391,19 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
++NumConstProp;
I->eraseFromParent();
RemoveFromWorkList(I);
Changed = true;
continue;
}
if (TD && I->getType()->getTypeID() == Type::VoidTyID) {
// See if we can constant fold its operands.
for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(i)) {
for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i)
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(i))
if (Constant *NewC = ConstantFoldConstantExpression(CE, TD))
i->set(NewC);
}
}
if (NewC != CE) {
i->set(NewC);
Changed = true;
}
}
// See if we can trivially sink this instruction to a successor basic block.

24
llvm/test/Transforms/InstCombine/dce-iterate.ll Normal file
View File

@ -0,0 +1,24 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret double .sy}
define internal double @ScaleObjectAdd(double %sx, double %sy, double %sz) nounwind {
entry:
%sx34 = bitcast double %sx to i64 ; <i64> [#uses=1]
%sx3435 = zext i64 %sx34 to i960 ; <i960> [#uses=1]
%sy22 = bitcast double %sy to i64 ; <i64> [#uses=1]
%sy2223 = zext i64 %sy22 to i960 ; <i960> [#uses=1]
%sy222324 = shl i960 %sy2223, 320 ; <i960> [#uses=1]
%sy222324.ins = or i960 %sx3435, %sy222324 ; <i960> [#uses=1]
%sz10 = bitcast double %sz to i64 ; <i64> [#uses=1]
%sz1011 = zext i64 %sz10 to i960 ; <i960> [#uses=1]
%sz101112 = shl i960 %sz1011, 640 ; <i960> [#uses=1]
%sz101112.ins = or i960 %sy222324.ins, %sz101112
%a = trunc i960 %sz101112.ins to i64 ; <i64> [#uses=1]
%b = bitcast i64 %a to double ; <double> [#uses=1]
%c = lshr i960 %sz101112.ins, 320 ; <i960> [#uses=1]
%d = trunc i960 %c to i64 ; <i64> [#uses=1]
%e = bitcast i64 %d to double ; <double> [#uses=1]
%f = add double %b, %e
ret double %e
}