[X86 fast-isel] Constrain the index reg class to not include SP.

The index reg on instructions with complex address modes is a GPR64_NOSP.  Constrain it to appease the machine verifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236557 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86FastISel.cpp

@@ -83,13 +83,13 @@ public:
 private:
   bool X86FastEmitCompare(const Value *LHS, const Value *RHS, EVT VT, DebugLoc DL);
 
-  bool X86FastEmitLoad(EVT VT, const X86AddressMode &AM, MachineMemOperand *MMO,
+  bool X86FastEmitLoad(EVT VT, X86AddressMode &AM, MachineMemOperand *MMO,
                        unsigned &ResultReg, unsigned Alignment = 1);
 
-  bool X86FastEmitStore(EVT VT, const Value *Val, const X86AddressMode &AM,
+  bool X86FastEmitStore(EVT VT, const Value *Val, X86AddressMode &AM,
                         MachineMemOperand *MMO = nullptr, bool Aligned = false);
   bool X86FastEmitStore(EVT VT, unsigned ValReg, bool ValIsKill,
-                        const X86AddressMode &AM,
+                        X86AddressMode &AM,
                         MachineMemOperand *MMO = nullptr, bool Aligned = false);
 
   bool X86FastEmitExtend(ISD::NodeType Opc, EVT DstVT, unsigned Src, EVT SrcVT,
@@ -165,6 +165,9 @@ private:
 
   bool foldX86XALUIntrinsic(X86::CondCode &CC, const Instruction *I,
                             const Value *Cond);
+
+  const MachineInstrBuilder &addFullAddress(const MachineInstrBuilder &MIB,
+                                            X86AddressMode &AM);
 };
 
 } // end anonymous namespace.
@@ -242,6 +245,20 @@ getX86SSEConditionCode(CmpInst::Predicate Predicate) {
   return std::make_pair(CC, NeedSwap);
 }
 
+/// \brief Adds a complex addressing mode to the given machine instr builder.
+/// Note, this will constrain the index register.  If its not possible to
+/// constrain the given index register, then a new one will be created.  The
+/// IndexReg field of the addressing mode will be updated to match in this case.
+const MachineInstrBuilder &
+X86FastISel::addFullAddress(const MachineInstrBuilder &MIB,
+                            X86AddressMode &AM) {
+  // First constrain the index register.  It needs to be a GR64_NOSP.
+  AM.IndexReg = constrainOperandRegClass(MIB->getDesc(), AM.IndexReg,
+                                         MIB->getNumOperands() +
+                                         X86::AddrIndexReg);
+  return ::addFullAddress(MIB, AM);
+}
+
 /// \brief Check if it is possible to fold the condition from the XALU intrinsic
 /// into the user. The condition code will only be updated on success.
 bool X86FastISel::foldX86XALUIntrinsic(X86::CondCode &CC, const Instruction *I,
@@ -326,7 +343,7 @@ bool X86FastISel::isTypeLegal(Type *Ty, MVT &VT, bool AllowI1) {
 /// X86FastEmitLoad - Emit a machine instruction to load a value of type VT.
 /// The address is either pre-computed, i.e. Ptr, or a GlobalAddress, i.e. GV.
 /// Return true and the result register by reference if it is possible.
-bool X86FastISel::X86FastEmitLoad(EVT VT, const X86AddressMode &AM,
+bool X86FastISel::X86FastEmitLoad(EVT VT, X86AddressMode &AM,
                                   MachineMemOperand *MMO, unsigned &ResultReg,
                                   unsigned Alignment) {
   // Get opcode and regclass of the output for the given load instruction.
@@ -413,7 +430,7 @@ bool X86FastISel::X86FastEmitLoad(EVT VT, const X86AddressMode &AM,
 /// and a displacement offset, or a GlobalAddress,
 /// i.e. V. Return true if it is possible.
 bool X86FastISel::X86FastEmitStore(EVT VT, unsigned ValReg, bool ValIsKill,
-                                   const X86AddressMode &AM,
+                                   X86AddressMode &AM,
                                    MachineMemOperand *MMO, bool Aligned) {
   // Get opcode and regclass of the output for the given store instruction.
   unsigned Opc = 0;
@@ -474,7 +491,7 @@ bool X86FastISel::X86FastEmitStore(EVT VT, unsigned ValReg, bool ValIsKill,
 }
 
 bool X86FastISel::X86FastEmitStore(EVT VT, const Value *Val,
-                                   const X86AddressMode &AM,
+                                   X86AddressMode &AM,
                                    MachineMemOperand *MMO, bool Aligned) {
   // Handle 'null' like i32/i64 0.
   if (isa<ConstantPointerNull>(Val))

test/CodeGen/X86/fast-isel-constrain-store-indexreg.ll

@@ -0,0 +1,25 @@
+; RUN: llc %s -o - -verify-machineinstrs | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-unknown"
+
+@TheArray = external global [100000 x double], align 16
+
+; This test ensures, via the machine verifier, that the register class for the
+; index of the double store is correctly constrained to not include SP.
+
+; CHECK: movsd
+
+define i32 @main(i32* %i, double %tmpv) {
+bb:
+  br label %bb7
+
+bb7:                                              ; preds = %bb7, %bb
+  %storemerge = phi i32 [ 0, %bb ], [ %tmp19, %bb7 ]
+  %tmp15 = zext i32 %storemerge to i64
+  %tmp16 = getelementptr inbounds [100000 x double], [100000 x double]* @TheArray, i64 0, i64 %tmp15
+  store double %tmpv, double* %tmp16, align 8
+  %tmp18 = load i32, i32* %i, align 4
+  %tmp19 = add i32 %tmp18, 1
+  br label %bb7
+}