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Fixed DAGCombine optimizations which generate select_cc for targets 

that do not support it (X86 does not lower select_cc).

PR: 13428

Together with Michael Kuperstein <michael.m.kuperstein@intel.com>

llvm-svn: 160619
This commit is contained in:
Nadav Rotem 2012-07-23 07:59:50 +00:00
parent 87f5dc53b2
commit 9056076cab
2 changed files with 65 additions and 32 deletions
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78
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -6002,29 +6002,36 @@ SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) {
return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0);
}
// fold (sint_to_fp (setcc x, y, cc)) -> (select_cc x, y, -1.0, 0.0,, cc)
if (N0.getOpcode() == ISD::SETCC && N0.getValueType() == MVT::i1 &&
!VT.isVector() &&
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
SDValue Ops[] =
{ N0.getOperand(0), N0.getOperand(1),
DAG.getConstantFP(-1.0, VT) , DAG.getConstantFP(0.0, VT),
N0.getOperand(2) };
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
}
// The next optimizations are desireable only if SELECT_CC can be lowered.
// Check against MVT::Other for SELECT_CC, which is a workaround for targets
// having to say they don't support SELECT_CC on every type the DAG knows
// about, since there is no way to mark an opcode illegal at all value types
// (See also visitSELECT)
if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other)) {
// fold (sint_to_fp (setcc x, y, cc)) -> (select_cc x, y, -1.0, 0.0,, cc)
if (N0.getOpcode() == ISD::SETCC && N0.getValueType() == MVT::i1 &&
!VT.isVector() &&
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
SDValue Ops[] =
{ N0.getOperand(0), N0.getOperand(1),
DAG.getConstantFP(-1.0, VT) , DAG.getConstantFP(0.0, VT),
N0.getOperand(2) };
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
}
// fold (sint_to_fp (zext (setcc x, y, cc))) ->
// (select_cc x, y, 1.0, 0.0,, cc)
if (N0.getOpcode() == ISD::ZERO_EXTEND &&
N0.getOperand(0).getOpcode() == ISD::SETCC &&!VT.isVector() &&
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
SDValue Ops[] =
{ N0.getOperand(0).getOperand(0), N0.getOperand(0).getOperand(1),
DAG.getConstantFP(1.0, VT) , DAG.getConstantFP(0.0, VT),
N0.getOperand(0).getOperand(2) };
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
// fold (sint_to_fp (zext (setcc x, y, cc))) ->
// (select_cc x, y, 1.0, 0.0,, cc)
if (N0.getOpcode() == ISD::ZERO_EXTEND &&
N0.getOperand(0).getOpcode() == ISD::SETCC &&!VT.isVector() &&
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
SDValue Ops[] =
{ N0.getOperand(0).getOperand(0), N0.getOperand(0).getOperand(1),
DAG.getConstantFP(1.0, VT) , DAG.getConstantFP(0.0, VT),
N0.getOperand(0).getOperand(2) };
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
}
}
return SDValue();
@ -6052,17 +6059,24 @@ SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) {
return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0);
}
// fold (uint_to_fp (setcc x, y, cc)) -> (select_cc x, y, -1.0, 0.0,, cc)
if (N0.getOpcode() == ISD::SETCC && !VT.isVector() &&
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
SDValue Ops[] =
{ N0.getOperand(0), N0.getOperand(1),
DAG.getConstantFP(1.0, VT), DAG.getConstantFP(0.0, VT),
N0.getOperand(2) };
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
}
// The next optimizations are desireable only if SELECT_CC can be lowered.
// Check against MVT::Other for SELECT_CC, which is a workaround for targets
// having to say they don't support SELECT_CC on every type the DAG knows
// about, since there is no way to mark an opcode illegal at all value types
// (See also visitSELECT)
if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other)) {
// fold (uint_to_fp (setcc x, y, cc)) -> (select_cc x, y, -1.0, 0.0,, cc)
if (N0.getOpcode() == ISD::SETCC && !VT.isVector() &&
(!LegalOperations ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT))) {
SDValue Ops[] =
{ N0.getOperand(0), N0.getOperand(1),
DAG.getConstantFP(1.0, VT), DAG.getConstantFP(0.0, VT),
N0.getOperand(2) };
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT, Ops, 5);
}
}
return SDValue();
}

19
llvm/test/CodeGen/X86/2012-07-23-select_cc.ll Normal file
View File

@ -0,0 +1,19 @@
; RUN: llc < %s -march=x86-64 -mcpu=corei7
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; PR 13428
declare void @use(double)
define void @test() {
entry:
call void @use(double 1.000000e+00)
%A = icmp eq i64 undef, 2
%B = zext i1 %A to i32
%C = sitofp i32 %B to double
call void @use(double %C)
call void @use(double 0.000000e+00)
unreachable
}