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| author | Nadav Rotem <nadav.rotem@intel.com> | 2011-02-24 21:01:34 +0000 |
|---|---|---|
| committer | Nadav Rotem <nadav.rotem@intel.com> | 2011-02-24 21:01:34 +0000 |
| commit | 8c20ec54d98176d31f310e4684d1d7f2ea0639bc (patch) | |
| tree | ac3c7cf68c4c21b8c368b8a758d6a2cf0ceae0f2 /lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| parent | 0412d5b40a3bde02580db6e3050ada0598205716 (diff) | |
| download | llvm-8c20ec54d98176d31f310e4684d1d7f2ea0639bc.tar.gz llvm-8c20ec54d98176d31f310e4684d1d7f2ea0639bc.tar.bz2 llvm-8c20ec54d98176d31f310e4684d1d7f2ea0639bc.tar.xz | |
Enable support for vector sext and trunc:
Limit the folding of any_ext and sext into the load operation to scalars.
Limit the active-bits trunc optimization to scalars.
Document vector trunc and vector sext in LangRef.
Similar to commit 126080 (for enabling zext).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126424 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index c5f0324ac4..911dbfd40f 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3685,7 +3685,9 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) { } // fold (sext (load x)) -> (sext (truncate (sextload x))) - if (ISD::isNON_EXTLoad(N0.getNode()) && + // None of the supported targets knows how to perform load and sign extend + // in one instruction. We only perform this transformation on scalars. + if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) { bool DoXform = true; @@ -4096,7 +4098,9 @@ SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) { } // fold (aext (load x)) -> (aext (truncate (extload x))) - if (ISD::isNON_EXTLoad(N0.getNode()) && + // None of the supported targets knows how to perform load and any_ext + // in one instruction. We only perform this transformation on scalars. + if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() && ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) || TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) { bool DoXform = true; @@ -4506,14 +4510,17 @@ SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { } // See if we can simplify the input to this truncate through knowledge that - // only the low bits are being used. For example "trunc (or (shl x, 8), y)" - // -> trunc y - SDValue Shorter = - GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(), - VT.getSizeInBits())); - if (Shorter.getNode()) - return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Shorter); - + // only the low bits are being used. + // For example "trunc (or (shl x, 8), y)" // -> trunc y + // Currenly we only perform this optimization on scalars because vectors + // may have different active low bits. + if (!VT.isVector()) { + SDValue Shorter = + GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(), + VT.getSizeInBits())); + if (Shorter.getNode()) + return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Shorter); + } // fold (truncate (load x)) -> (smaller load x) // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits)) if (!LegalTypes || TLI.isTypeDesirableForOp(N0.getOpcode(), VT)) { |