Factor out the code for sign-extending/truncating gep indices
and use it in x86 address mode folding. Also, make
getRegForValue return 0 for illegal types even if it has a
ValueMap for them, because Argument values are put in the
ValueMap. This fixes PR3181.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60696 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index 037a46d..3d0348d 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -55,6 +55,19 @@
 using namespace llvm;
 
 unsigned FastISel::getRegForValue(Value *V) {
+  MVT::SimpleValueType VT = TLI.getValueType(V->getType()).getSimpleVT();
+
+  // Ignore illegal types. We must do this before looking up the value
+  // in ValueMap because Arguments are given virtual registers regardless
+  // of whether FastISel can handle them.
+  if (!TLI.isTypeLegal(VT)) {
+    // Promote MVT::i1 to a legal type though, because it's common and easy.
+    if (VT == MVT::i1)
+      VT = TLI.getTypeToTransformTo(VT).getSimpleVT();
+    else
+      return 0;
+  }
+
   // Look up the value to see if we already have a register for it. We
   // cache values defined by Instructions across blocks, and other values
   // only locally. This is because Instructions already have the SSA
@@ -65,17 +78,6 @@
   if (Reg != 0)
     return Reg;
 
-  MVT::SimpleValueType VT = TLI.getValueType(V->getType()).getSimpleVT();
-
-  // Ignore illegal types.
-  if (!TLI.isTypeLegal(VT)) {
-    // Promote MVT::i1 to a legal type though, because it's common and easy.
-    if (VT == MVT::i1)
-      VT = TLI.getTypeToTransformTo(VT).getSimpleVT();
-    else
-      return 0;
-  }
-
   if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
     if (CI->getValue().getActiveBits() <= 64)
       Reg = FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue());
@@ -153,6 +155,24 @@
                      Reg, MRI.getRegClass(Reg), MRI.getRegClass(Reg));
 }
 
+unsigned FastISel::getRegForGEPIndex(Value *Idx) {
+  unsigned IdxN = getRegForValue(Idx);
+  if (IdxN == 0)
+    // Unhandled operand. Halt "fast" selection and bail.
+    return 0;
+
+  // If the index is smaller or larger than intptr_t, truncate or extend it.
+  MVT PtrVT = TLI.getPointerTy();
+  MVT IdxVT = MVT::getMVT(Idx->getType(), /*HandleUnknown=*/false);
+  if (IdxVT.bitsLT(PtrVT))
+    IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT.getSimpleVT(),
+                      ISD::SIGN_EXTEND, IdxN);
+  else if (IdxVT.bitsGT(PtrVT))
+    IdxN = FastEmit_r(IdxVT.getSimpleVT(), PtrVT.getSimpleVT(),
+                      ISD::TRUNCATE, IdxN);
+  return IdxN;
+}
+
 /// SelectBinaryOp - Select and emit code for a binary operator instruction,
 /// which has an opcode which directly corresponds to the given ISD opcode.
 ///
@@ -263,18 +283,7 @@
       
       // N = N + Idx * ElementSize;
       uint64_t ElementSize = TD.getABITypeSize(Ty);
-      unsigned IdxN = getRegForValue(Idx);
-      if (IdxN == 0)
-        // Unhandled operand. Halt "fast" selection and bail.
-        return false;
-
-      // If the index is smaller or larger than intptr_t, truncate or extend
-      // it.
-      MVT IdxVT = MVT::getMVT(Idx->getType(), /*HandleUnknown=*/false);
-      if (IdxVT.bitsLT(VT))
-        IdxN = FastEmit_r(IdxVT.getSimpleVT(), VT, ISD::SIGN_EXTEND, IdxN);
-      else if (IdxVT.bitsGT(VT))
-        IdxN = FastEmit_r(IdxVT.getSimpleVT(), VT, ISD::TRUNCATE, IdxN);
+      unsigned IdxN = getRegForGEPIndex(Idx);
       if (IdxN == 0)
         // Unhandled operand. Halt "fast" selection and bail.
         return false;