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| author | Simon Pilgrim <llvm-dev@redking.me.uk> | 2016-09-18 12:45:23 +0000 |
|---|---|---|
| committer | Simon Pilgrim <llvm-dev@redking.me.uk> | 2016-09-18 12:45:23 +0000 |
| commit | 6c21e6a54e7aa2eb9878b1075eade08d4fdb9f32 (patch) | |
| tree | fb1aeaa228fc4be70e9cd8a5e11bf54ef36a59ea /llvm/lib/CodeGen/SelectionDAG | |
| parent | a1a0e7ddbec054373876b61fa680049385cb6cf9 (diff) | |
| download | bcm5719-llvm-6c21e6a54e7aa2eb9878b1075eade08d4fdb9f32.tar.gz bcm5719-llvm-6c21e6a54e7aa2eb9878b1075eade08d4fdb9f32.zip | |
[X86][SSE] Improve recognition of uitofp conversions that can be performed as sitofp
With D24253 we can now use SelectionDAG::SignBitIsZero with vector operations.
This patch uses SelectionDAG::SignBitIsZero to recognise that a zero sign bit means that we can use a sitofp instead of a uitofp (which is not directly support on pre-AVX512 hardware).
While AVX512 does provide support for uitofp, the conversion to sitofp should not cause any regressions.
Differential Revision: https://reviews.llvm.org/D24343
llvm-svn: 281852
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 309be2c2253..570c26a42ed 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -1980,10 +1980,6 @@ SDValue SelectionDAG::FoldSetCC(EVT VT, SDValue N1, SDValue N2, /// SignBitIsZero - Return true if the sign bit of Op is known to be zero. We /// use this predicate to simplify operations downstream. bool SelectionDAG::SignBitIsZero(SDValue Op, unsigned Depth) const { - // This predicate is not safe for vector operations. - if (Op.getValueType().isVector()) - return false; - unsigned BitWidth = Op.getScalarValueSizeInBits(); return MaskedValueIsZero(Op, APInt::getSignBit(BitWidth), Depth); } |
