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Implement some trivial FP foldings when -enable-unsafe-fp-math is specified.

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This implements CodeGen/PowerPC/unsafe-math.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33024 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-01-08 23:04:05 +00:00
parent cc78156a15
commit ddae4bd683
1 changed files with 15 additions and 0 deletions
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15
lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -35,6 +35,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/CommandLine.h"
#include <algorithm>
@ -2401,6 +2402,13 @@ SDOperand DAGCombiner::visitFADD(SDNode *N) {
// fold ((-A) + B) -> B-A
if (N0.getOpcode() == ISD::FNEG)
return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0));
// If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2))
if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD &&
N0.Val->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
return DAG.getNode(ISD::FADD, VT, N0.getOperand(0),
DAG.getNode(ISD::FADD, VT, N0.getOperand(1), N1));
return SDOperand();
}
@ -2436,6 +2444,13 @@ SDOperand DAGCombiner::visitFMUL(SDNode *N) {
// fold (fmul X, 2.0) -> (fadd X, X)
if (N1CFP && N1CFP->isExactlyValue(+2.0))
return DAG.getNode(ISD::FADD, VT, N0, N0);
// If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2))
if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL &&
N0.Val->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
return DAG.getNode(ISD::FMUL, VT, N0.getOperand(0),
DAG.getNode(ISD::FMUL, VT, N0.getOperand(1), N1));
return SDOperand();
}