LowerFP_TO_SINT must not create a stack object if it's not needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43004 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 24 insertions, 6 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index bac658f85e..8726c587ca 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -3895,13 +3895,7 @@ SDOperand X86TargetLowering::LowerSINT_TO_FP(SDOperand Op, SelectionDAG &DAG) {
 SDOperand X86TargetLowering::LowerFP_TO_SINT(SDOperand Op, SelectionDAG &DAG) {
   assert(Op.getValueType() <= MVT::i64 && Op.getValueType() >= MVT::i16 &&
          "Unknown FP_TO_SINT to lower!");
-  // We lower FP->sint64 into FISTP64, followed by a load, all to a temporary
-  // stack slot.
   SDOperand Result;
-  MachineFunction &MF = DAG.getMachineFunction();
-  unsigned MemSize = MVT::getSizeInBits(Op.getValueType())/8;
-  int SSFI = MF.getFrameInfo()->CreateStackObject(MemSize, MemSize);
-  SDOperand StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
 
   // These are really Legal.
   if (Op.getValueType() == MVT::i32 && 
@@ -3915,6 +3909,12 @@ SDOperand X86TargetLowering::LowerFP_TO_SINT(SDOperand Op, SelectionDAG &DAG) {
       Op.getOperand(0).getValueType() != MVT::f80)
     return Result;
 
+  // We lower FP->sint64 into FISTP64, followed by a load, all to a temporary
+  // stack slot.
+  MachineFunction &MF = DAG.getMachineFunction();
+  unsigned MemSize = MVT::getSizeInBits(Op.getValueType())/8;
+  int SSFI = MF.getFrameInfo()->CreateStackObject(MemSize, MemSize);
+  SDOperand StackSlot = DAG.getFrameIndex(SSFI, getPointerTy());
   unsigned Opc;
   switch (Op.getValueType()) {
     default: assert(0 && "Invalid FP_TO_SINT to lower!");
diff --git a/test/CodeGen/X86/fp2sint.ll b/test/CodeGen/X86/fp2sint.ll
new file mode 100644
index 0000000000..80f7efbe4d
--- /dev/null
+++ b/test/CodeGen/X86/fp2sint.ll
@@ -0,0 +1,18 @@
+;; LowerFP_TO_SINT should not create a stack object if it's not needed.
+
+; RUN: llvm-as < %s | llc -march=x86 -mattr=+sse2 | not grep add
+
+define i32 @main(i32 %argc, i8** %argv) {
+cond_false.i.i.i:               ; preds = %bb.i5
+       %tmp35.i = load double* null, align 8           ; <double> [#uses=1]
+       %tmp3536.i = fptosi double %tmp35.i to i32              ; <i32> [#uses=1]
+       %tmp3536140.i = zext i32 %tmp3536.i to i64              ; <i64> [#uses=1]
+       %tmp39.i = load double* null, align 4           ; <double> [#uses=1]
+       %tmp3940.i = fptosi double %tmp39.i to i32              ; <i32> [#uses=1]
+       %tmp3940137.i = zext i32 %tmp3940.i to i64              ; <i64> [#uses=1]
+       %tmp3940137138.i = shl i64 %tmp3940137.i, 32            ; <i64> [#uses=1]
+       %tmp3940137138.ins.i = or i64 %tmp3940137138.i, %tmp3536140.i           ; <i64> [#uses=1]
+       %tmp95.i.i = trunc i64 %tmp3940137138.ins.i to i32              ; <i32> [#uses=1]
+       store i32 %tmp95.i.i, i32* null, align 4
+       ret i32 0
+}