AMDGPU: Always use VGPR indexing on GFX9

Reviewers: arsenm

Subscribers: kzhuravl, wdng, nhaehnle, yaxunl, tony-tye, dstuttard, tpr

Differential Revision: https://reviews.llvm.org/D31157

llvm-svn: 298396

3 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPU.td b/llvm/lib/Target/AMDGPU/AMDGPU.td
index 43e900109f7..2c7a2d8962d 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPU.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPU.td
@@ -406,7 +406,7 @@ def FeatureGFX9 : SubtargetFeatureGeneration<"GFX9",
    FeatureWavefrontSize64, FeatureFlatAddressSpace, FeatureGCN,
    FeatureGCN3Encoding, FeatureCIInsts, Feature16BitInsts,
    FeatureSMemRealTime, FeatureScalarStores, FeatureInv2PiInlineImm,
-   FeatureApertureRegs, FeatureGFX9Insts, FeatureVOP3P
+   FeatureApertureRegs, FeatureGFX9Insts, FeatureVOP3P, FeatureVGPRIndexMode
   ]
 >;
 
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
index 4bd4d41d752..39289d0f149 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
@@ -625,6 +625,10 @@ public:
     return HasVGPRIndexMode;
   }
 
+  bool useVGPRIndexMode(bool UserEnable) const {
+    return !hasMovrel() || (UserEnable && hasVGPRIndexMode());
+  }
+
   bool hasScalarCompareEq64() const {
     return getGeneration() >= VOLCANIC_ISLANDS;
   }
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index dfdc233d09d..ea7d3745d38 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -1667,7 +1667,7 @@ static MachineBasicBlock *emitIndirectSrc(MachineInstr &MI,
   std::tie(SubReg, Offset)
     = computeIndirectRegAndOffset(TRI, VecRC, SrcReg, Offset);
 
-  bool UseGPRIdxMode = ST.hasVGPRIndexMode() && EnableVGPRIndexMode;
+  bool UseGPRIdxMode = ST.useVGPRIndexMode(EnableVGPRIndexMode);
 
   if (setM0ToIndexFromSGPR(TII, MRI, MI, Offset, UseGPRIdxMode, true)) {
     MachineBasicBlock::iterator I(&MI);
@@ -1769,7 +1769,7 @@ static MachineBasicBlock *emitIndirectDst(MachineInstr &MI,
   std::tie(SubReg, Offset) = computeIndirectRegAndOffset(TRI, VecRC,
                                                          SrcVec->getReg(),
                                                          Offset);
-  bool UseGPRIdxMode = ST.hasVGPRIndexMode() && EnableVGPRIndexMode;
+  bool UseGPRIdxMode = ST.useVGPRIndexMode(EnableVGPRIndexMode);
 
   if (Idx->getReg() == AMDGPU::NoRegister) {
     MachineBasicBlock::iterator I(&MI);