[SDAG] Don't try to use FP_EXTEND/FP_ROUND for int<->fp promotions

The PowerPC backend has long promoted some floating-point vector operations
(such as select) to integer vector operations. Unfortunately, this behavior was
broken by r216555. When using FP_EXTEND/FP_ROUND for promotions, we must check
that both the old and new types are floating-point types. Otherwise, we must
use BITCAST as we did prior to r216555 for everything.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228969 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index 11e6b38..3a8c276 100644 (file)
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -390,7 +390,8 @@ SDValue VectorLegalizer::Promote(SDValue Op) {
       if (Op.getOperand(j)
               .getValueType()
               .getVectorElementType()
-              .isFloatingPoint())
+              .isFloatingPoint() &&
+          NVT.isVector() && NVT.getVectorElementType().isFloatingPoint())
         Operands[j] = DAG.getNode(ISD::FP_EXTEND, dl, NVT, Op.getOperand(j));
       else
         Operands[j] = DAG.getNode(ISD::BITCAST, dl, NVT, Op.getOperand(j));
@@ -399,8 +400,9 @@ SDValue VectorLegalizer::Promote(SDValue Op) {
   }
 
   Op = DAG.getNode(Op.getOpcode(), dl, NVT, Operands);
-  if (VT.isFloatingPoint() ||
-      (VT.isVector() && VT.getVectorElementType().isFloatingPoint()))
+  if ((VT.isFloatingPoint() && NVT.isFloatingPoint()) ||
+      (VT.isVector() && VT.getVectorElementType().isFloatingPoint() &&
+       NVT.isVector() && NVT.getVectorElementType().isFloatingPoint()))
     return DAG.getNode(ISD::FP_ROUND, dl, VT, Op, DAG.getIntPtrConstant(0));
   else
     return DAG.getNode(ISD::BITCAST, dl, VT, Op);

diff --git a/test/CodeGen/PowerPC/vsel-prom.ll b/test/CodeGen/PowerPC/vsel-prom.ll
new file mode 100644 (file)
index 0000000..dd219ec
--- /dev/null
+++ b/test/CodeGen/PowerPC/vsel-prom.ll
@@ -0,0 +1,23 @@
+; RUN: llc -mcpu=pwr7 < %s | FileCheck %s
+target datalayout = "E-m:e-i64:64-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+; Function Attrs: nounwind
+define void @Compute_Lateral() #0 {
+entry:
+  br i1 undef, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  unreachable
+
+if.end:                                           ; preds = %entry
+  %0 = select i1 undef, <2 x double> undef, <2 x double> zeroinitializer
+  %1 = extractelement <2 x double> %0, i32 1
+  store double %1, double* undef, align 8
+  ret void
+
+; CHECK-LABEL: @Compute_Lateral
+}
+
+attributes #0 = { nounwind }
+