PowerPC: Don't lower SELECT_CC to PPCISD::FSEL on SPE

[jhibbits]

Summary

SPE doesn't have a fsel instruction, so don't try to lower to it.

This fixes a "Cannot select: tN: f64 = PPCISD::FSEL tX, tY, tZ" error.

[lkail]

LGTM. Please hold on a couple of days in case others have comments.

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

7803

nit: Move this line to the above(clang-format might comment in a wrong line :o).

llvm/test/CodeGen/PowerPC/spe-fastmath.ll

4

nit: 2-space indentation against last line should be enough.

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

SDValue PPCTargetLowering::LowerTRUNCATEVector(SDValue Op,
 
   SDValue Conv = DAG.getNode(ISD::BITCAST, DL, WideVT, WideSrc);
   return DAG.getVectorShuffle(WideVT, DL, Conv, DAG.getUNDEF(WideVT), ShuffV);
 }
 
 /// LowerSELECT_CC - Lower floating point select_cc's into fsel instruction when
 /// possible.
 SDValue PPCTargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const {
-  // Not FP? Not a fsel.
+  // Not FP, or using SPE? Not a fsel.
   if (!Op.getOperand(0).getValueType().isFloatingPoint() ||
-      !Op.getOperand(2).getValueType().isFloatingPoint())
+      !Op.getOperand(2).getValueType().isFloatingPoint() || Subtarget.hasSPE())
     return Op;
 
   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
 
   EVT ResVT = Op.getValueType();
   EVT CmpVT = Op.getOperand(0).getValueType();
   SDValue LHS = Op.getOperand(0), RHS = Op.getOperand(1);
   SDValue TV  = Op.getOperand(2), FV  = Op.getOperand(3);
   SDLoc dl(Op);

llvm/test/CodeGen/PowerPC/spe-fastmath.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc-unknown-linux-gnu \
+; RUN:   -mattr=+spe |  FileCheck %s
+
+define void @no_fsel(i32 %e) #0 {
+; CHECK-LABEL: no_fsel:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    li 4, .LCPI0_0@l
+; CHECK-NEXT:    lis 5, .LCPI0_0@ha
+; CHECK-NEXT:    evlddx 4, 5, 4
+; CHECK-NEXT:    efdcfui 3, 3
+; CHECK-NEXT:    efdmul 5, 3, 3
+; CHECK-NEXT:    efdcmpeq 0, 5, 4
+; CHECK-NEXT:    ble 0, .LBB0_2
+; CHECK-NEXT:  # %bb.1: # %entry
+; CHECK-NEXT:    evor 3, 4, 4
+; CHECK-NEXT:  .LBB0_2: # %entry
+; CHECK-NEXT:    efdctsiz 3, 3
+; CHECK-NEXT:    sth 3, 0(3)
+; CHECK-NEXT:    blr
+entry:
+  %conv = uitofp i32 %e to double
+  %mul = fmul double %conv, %conv
+  %tobool = fcmp une double %mul, 0.000000e+00
+  %cond = select i1 %tobool, double %conv, double 0.000000e+00
+  %conv3 = fptosi double %cond to i16
+  store i16 %conv3, i16* undef
+  ret void
+}
+
+attributes #0 = { "no-infs-fp-math"="true" "no-nans-fp-math"="true" }