[AMDGPU] SDWA: several fixes for V_CVT and VOPC instructions

Summary:
1. Instruction V_CVT_U32_F32 allow omod operand (see SIInstrInfo.td:1435). In fact this operand shouldn't be allowed here. This fix checks if SDWA pseudo instruction has OMod operand and then copy it.
2. There were several problems with support of VOPC instructions in SDWA peephole pass.

Reviewers: tstellar, arsenm, vpykhtin, airlied, kzhuravl

Subscribers: wdng, nhaehnle, yaxunl, dstuttard, tpr, sarnex, t-tye

Differential Revision: https://reviews.llvm.org/D34626

llvm-svn: 306413

6 files changed, 43 insertions, 33 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPU.td b/llvm/lib/Target/AMDGPU/AMDGPU.td
index 7494e5decd6..f1d899c4d00 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPU.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPU.td
@@ -262,8 +262,8 @@ def FeatureSDWAMac : SubtargetFeature<"sdwa-mav",
   "Support v_mac_f32/f16 with SDWA (Sub-DWORD Addressing) extension"
 >;
 
-def FeatureSDWAClampVOPC : SubtargetFeature<"sdwa-clamp-vopc",
-  "HasSDWAClampVOPC",
+def FeatureSDWAOutModsVOPC : SubtargetFeature<"sdwa-out-mods-vopc",
+  "HasSDWAOutModsVOPC",
   "true",
   "Support clamp for VOPC with SDWA (Sub-DWORD Addressing) extension"
 >;
@@ -452,7 +452,7 @@ def FeatureVolcanicIslands : SubtargetFeatureGeneration<"VOLCANIC_ISLANDS",
    FeatureGCN3Encoding, FeatureCIInsts, Feature16BitInsts,
    FeatureSMemRealTime, FeatureVGPRIndexMode, FeatureMovrel,
    FeatureScalarStores, FeatureInv2PiInlineImm,
-   FeatureSDWA, FeatureSDWAClampVOPC, FeatureSDWAMac, FeatureDPP
+   FeatureSDWA, FeatureSDWAOutModsVOPC, FeatureSDWAMac, FeatureDPP
   ]
 >;
 
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
index ab5abf2039a..be47b900c6f 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
@@ -128,7 +128,7 @@ AMDGPUSubtarget::AMDGPUSubtarget(const Triple &TT, StringRef GPU, StringRef FS,
     HasSDWAScalar(false),
     HasSDWASdst(false),
     HasSDWAMac(false),
-    HasSDWAClampVOPC(false),
+    HasSDWAOutModsVOPC(false),
     HasDPP(false),
     FlatAddressSpace(false),
     FlatInstOffsets(false),
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
index 2b16289c723..22cede59086 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
@@ -153,7 +153,7 @@ protected:
   bool HasSDWAScalar;
   bool HasSDWASdst;
   bool HasSDWAMac;
-  bool HasSDWAClampVOPC;
+  bool HasSDWAOutModsVOPC;
   bool HasDPP;
   bool FlatAddressSpace;
   bool FlatInstOffsets;
@@ -452,8 +452,8 @@ public:
     return HasSDWAMac;
   }
 
-  bool hasSDWAClampVOPC() const {
-    return HasSDWAClampVOPC;
+  bool hasSDWAOutModsVOPC() const {
+    return HasSDWAOutModsVOPC;
   }
 
   /// \brief Returns the offset in bytes from the start of the input buffer
diff --git a/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp b/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp
index 04308fb3aaf..f26e49295e6 100644
--- a/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp
+++ b/llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp
@@ -626,7 +626,9 @@ MCOperand AMDGPUDisassembler::decodeSDWASrc(const OpWidthTy Width,
   using namespace AMDGPU::SDWA;
 
   if (STI.getFeatureBits()[AMDGPU::FeatureGFX9]) {
-    if (SDWA9EncValues::SRC_VGPR_MIN <= Val &&
+    // XXX: static_cast<int> is needed to avoid stupid warning:
+    // compare with unsigned is always true
+    if (SDWA9EncValues::SRC_VGPR_MIN <= static_cast<int>(Val) &&
         Val <= SDWA9EncValues::SRC_VGPR_MAX) {
       return createRegOperand(getVgprClassId(Width),
                               Val - SDWA9EncValues::SRC_VGPR_MIN);
diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index 4dd0d5b2199..b6784ec14e9 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -2444,8 +2444,6 @@ bool SIInstrInfo::verifyInstruction(const MachineInstr &MI,
     }
 
     int DstIdx = AMDGPU::getNamedOperandIdx(Opcode, AMDGPU::OpName::vdst);
-    if ( DstIdx == -1)
-      DstIdx = AMDGPU::getNamedOperandIdx(Opcode, AMDGPU::OpName::sdst);
 
     const int OpIndicies[] = { DstIdx, Src0Idx, Src1Idx, Src2Idx };
 
@@ -2488,14 +2486,20 @@ bool SIInstrInfo::verifyInstruction(const MachineInstr &MI,
           ErrInfo = "Only VCC allowed as dst in SDWA instructions on VI";
           return false;
         }
-      } else if (!ST.hasSDWAClampVOPC()) {
+      } else if (!ST.hasSDWAOutModsVOPC()) {
         // No clamp allowed on GFX9 for VOPC
         const MachineOperand *Clamp = getNamedOperand(MI, AMDGPU::OpName::clamp);
-        if (Clamp != nullptr &&
-          (!Clamp->isImm() || Clamp->getImm() != 0)) {
+        if (Clamp && (!Clamp->isImm() || Clamp->getImm() != 0)) {
           ErrInfo = "Clamp not allowed in VOPC SDWA instructions on VI";
           return false;
         }
+
+        // No omod allowed on GFX9 for VOPC
+        const MachineOperand *OMod = getNamedOperand(MI, AMDGPU::OpName::omod);
+        if (OMod && (!OMod->isImm() || OMod->getImm() != 0)) {
+          ErrInfo = "OMod not allowed in VOPC SDWA instructions on VI";
+          return false;
+        }
       }
     }
   }
diff --git a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
index 4ac23ef03cb..e2ac6631d2f 100644
--- a/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
+++ b/llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp
@@ -627,10 +627,13 @@ bool SIPeepholeSDWA::isConvertibleToSDWA(const MachineInstr &MI,
         return false;
     }
 
-    if (!ST.hasSDWAClampVOPC() && TII->hasModifiersSet(MI, AMDGPU::OpName::clamp))
+    if (!ST.hasSDWAOutModsVOPC() &&
+        (TII->hasModifiersSet(MI, AMDGPU::OpName::clamp) ||
+         TII->hasModifiersSet(MI, AMDGPU::OpName::omod)))
       return false;
 
-  } else if (TII->getNamedOperand(MI, AMDGPU::OpName::sdst)) {
+  } else if (TII->getNamedOperand(MI, AMDGPU::OpName::sdst) ||
+             !TII->getNamedOperand(MI, AMDGPU::OpName::vdst)) {
     return false;
   }
 
@@ -649,25 +652,24 @@ bool SIPeepholeSDWA::convertToSDWA(MachineInstr &MI,
     SDWAOpcode = AMDGPU::getSDWAOp(AMDGPU::getVOPe32(MI.getOpcode()));
   assert(SDWAOpcode != -1);
 
-  // Copy dst, if it is present in original then should also be present in SDWA
-  MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
-  if (!Dst && !TII->isVOPC(MI))
-    return false;
-
   const MCInstrDesc &SDWADesc = TII->get(SDWAOpcode);
 
   // Create SDWA version of instruction MI and initialize its operands
   MachineInstrBuilder SDWAInst =
     BuildMI(*MI.getParent(), MI, MI.getDebugLoc(), SDWADesc);
 
+  // Copy dst, if it is present in original then should also be present in SDWA
+  MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
   if (Dst) {
     assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::vdst) != -1);
     SDWAInst.add(*Dst);
-  } else {
-    Dst = TII->getNamedOperand(MI, AMDGPU::OpName::sdst);
+  } else if ((Dst = TII->getNamedOperand(MI, AMDGPU::OpName::sdst))) {
     assert(Dst &&
            AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::sdst) != -1);
     SDWAInst.add(*Dst);
+  } else {
+    assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::sdst) != -1);
+    SDWAInst.addReg(AMDGPU::VCC, RegState::Define);
   }
 
   // Copy src0, initialize src0_modifiers. All sdwa instructions has src0 and
@@ -714,20 +716,22 @@ bool SIPeepholeSDWA::convertToSDWA(MachineInstr &MI,
   }
 
   // Copy omod if present, initialize otherwise if needed
-  MachineOperand *OMod = TII->getNamedOperand(MI, AMDGPU::OpName::omod);
-  if (OMod) {
-    assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::omod) != -1);
-    SDWAInst.add(*OMod);
-  } else if (AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::omod) != -1) {
-    SDWAInst.addImm(0);
+  if (AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::omod) != -1) {
+    MachineOperand *OMod = TII->getNamedOperand(MI, AMDGPU::OpName::omod);
+    if (OMod) {
+      SDWAInst.add(*OMod);
+    } else {
+      SDWAInst.addImm(0);
+    }
   }
 
-  // Initialize dst_sel and dst_unused if present
-  if (Dst) {
-    assert(
-      AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::dst_sel) != -1 &&
-      AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::dst_unused) != -1);
+  // Initialize dst_sel if present
+  if (AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::dst_sel) != -1) {
     SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
+  }
+
+  // Initialize dst_unused if present
+  if (AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::dst_unused) != -1) {
     SDWAInst.addImm(AMDGPU::SDWA::DstUnused::UNUSED_PAD);
   }