[GlobalISel][Legalizer] Convert the FP constants to the right APFloat type for G_FCONSTANT.
We weren't converting the immediate ConstantFP during legalization, which caused
the wrong bit patterns to be emitted for half type FP constants.
Fixes PR36106.
llvm-svn: 323582
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index d8dc936e..06e3c75 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -715,7 +715,24 @@
}
case TargetOpcode::G_FCONSTANT: {
unsigned DstExt = MRI.createGenericVirtualRegister(WideTy);
- MIRBuilder.buildFConstant(DstExt, *MI.getOperand(1).getFPImm());
+ const ConstantFP *CFP = MI.getOperand(1).getFPImm();
+ APFloat Val = CFP->getValueAPF();
+ LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
+ auto LLT2Sem = [](LLT Ty) {
+ switch (Ty.getSizeInBits()) {
+ case 32:
+ return &APFloat::IEEEsingle();
+ break;
+ case 64:
+ return &APFloat::IEEEdouble();
+ break;
+ default:
+ llvm_unreachable("Unhandled fp widen type");
+ }
+ };
+ bool LosesInfo;
+ Val.convert(*LLT2Sem(WideTy), APFloat::rmTowardZero, &LosesInfo);
+ MIRBuilder.buildFConstant(DstExt, *ConstantFP::get(Ctx, Val));
MIRBuilder.buildFPTrunc(MI.getOperand(0).getReg(), DstExt);
MI.eraseFromParent();
return Legalized;
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-constant.mir b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-constant.mir
index 4ed84ed..c3ed331 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-constant.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-constant.mir
@@ -75,7 +75,7 @@
; CHECK: %w0 = COPY [[C]](s32)
; CHECK: [[C1:%[0-9]+]]:_(s64) = G_FCONSTANT double 2.000000e+00
; CHECK: %x0 = COPY [[C1]](s64)
- ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_FCONSTANT half 0xH0000
+ ; CHECK: [[C2:%[0-9]+]]:_(s32) = G_FCONSTANT float 0.000000e+00
; CHECK: [[FPTRUNC:%[0-9]+]]:_(s16) = G_FPTRUNC [[C2]](s32)
; CHECK: [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[FPTRUNC]](s16)
; CHECK: %w0 = COPY [[ANYEXT]](s32)