[PowerPC] Skip IEEE 128-bit FP type in FastISel

[qiucf]

Summary

Vector types, quadword integers and f128 currently cannot be handled in FastISel. We did not skip f128 type in lowering arguments, which causes a crash.

[qiucf]

Skip f128 in FastISel.

[qiucf]

Add comments

[steven.zhang]

llvm/lib/Target/PowerPC/PPCFastISel.cpp

1629

So, this is a TODO ?

[qiucf]

Mark as 'FIXME'

[steven.zhang]

LGTM.

llvm/lib/Target/PowerPC/PPCFastISel.cpp

if (Flags.isInReg() || Flags.isSRet() || Flags.isNest() || Flags.isByVal())
       return false;
 
     Value *ArgValue = CLI.OutVals[i];
     Type *ArgTy = ArgValue->getType();
     MVT ArgVT;
     if (!isTypeLegal(ArgTy, ArgVT) && ArgVT != MVT::i16 && ArgVT != MVT::i8)
       return false;
 
-    if (ArgVT.isVector())
+    // FIXME: FastISel cannot handle non-simple types yet, including 128-bit FP
+    // types, which is passed through vector register. Skip these types and
+    // fallback to default SelectionDAG based selection.
+    if (ArgVT.isVector() || ArgVT == MVT::f128)
       return false;
 
     unsigned Arg = getRegForValue(ArgValue);
     if (Arg == 0)
       return false;
 
     Args.push_back(ArgValue);
     ArgRegs.push_back(Arg);

llvm/test/CodeGen/PowerPC/f128-passByValue.ll

entry:
   store <4 x i32> %vec1, <4 x i32>* %vec2, align 16
   %0 = load fp128, fp128* %f2, align 16
   %conv = sitofp i32 %i1 to fp128
   %add = fadd fp128 %0, %conv
   %conv1 = fptrunc fp128 %add to double
   store double %conv1, double* %d1, align 8
   ret void
 }
+
+; Function Attrs: noinline optnone
+define signext i32 @noopt_call_crash() #0 {
+; CHECK-LABEL: noopt_call_crash:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    mflr r0
+; CHECK-NEXT:    std r0, 16(r1)
+; CHECK-NEXT:    stdu r1, -96(r1)
+; CHECK-NEXT:    .cfi_def_cfa_offset 96
+; CHECK-NEXT:    .cfi_offset lr, 16
+; CHECK-NEXT:    bl in
+; CHECK-NEXT:    nop
+; CHECK-NEXT:    bl out
+; CHECK-NEXT:    nop
+; CHECK-NEXT:    li r3, 0
+; CHECK-NEXT:    addi r1, r1, 96
+; CHECK-NEXT:    ld r0, 16(r1)
+; CHECK-NEXT:    mtlr r0
+; CHECK-NEXT:    blr
+entry:
+  %call = call fp128 @in()
+  call void @out(fp128 %call)
+  ret i32 0
+}
+
+declare void @out(fp128)
+declare fp128 @in()
+
+attributes #0 = { noinline optnone }