commit fe2ee4c46a0027d2f1c406be6e6345f587226851
author Dmitry Preobrazhensky <dmitry.preobrazhensky@amd.com> Mon Sep 02 12:50:05 2019 +0000
committer Dmitry Preobrazhensky <dmitry.preobrazhensky@amd.com> Mon Sep 02 12:50:05 2019 +0000
tree a4516ccb5b46f8b8ab21a2565fa45da65d31bdf4
parent a1ad72cca7eac7a0e9eed953f7f0da8cf2e63144

[AMDGPU][MC][GFX10] Corrected constant bus limit for 64-bit shift instructions

See bug 42744: https://bugs.llvm.org/show_bug.cgi?id=42744

Reviewers: atamazov, arsenm

Differential Revision: https://reviews.llvm.org/D65228

llvm-svn: 370652

llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp

diff --git a/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp b/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
index 77399e3..ab9e0a9 100644
--- a/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
+++ b/llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp
@@ -1309,6 +1309,7 @@
   bool validateOpSel(const MCInst &Inst);
   bool validateVccOperand(unsigned Reg) const;
   bool validateVOP3Literal(const MCInst &Inst) const;
+  unsigned getConstantBusLimit(unsigned Opcode) const;
   bool usesConstantBus(const MCInst &Inst, unsigned OpIdx);
   bool isInlineConstant(const MCInst &Inst, unsigned OpIdx) const;
   unsigned findImplicitSGPRReadInVOP(const MCInst &Inst) const;
@@ -2703,6 +2704,27 @@
   }
 }
 
+unsigned AMDGPUAsmParser::getConstantBusLimit(unsigned Opcode) const {
+  if (!isGFX10())
+    return 1;
+
+  switch (Opcode) {
+  // 64-bit shift instructions can use only one scalar value input
+  case AMDGPU::V_LSHLREV_B64:
+  case AMDGPU::V_LSHLREV_B64_gfx10:
+  case AMDGPU::V_LSHL_B64:
+  case AMDGPU::V_LSHRREV_B64:
+  case AMDGPU::V_LSHRREV_B64_gfx10:
+  case AMDGPU::V_LSHR_B64:
+  case AMDGPU::V_ASHRREV_I64:
+  case AMDGPU::V_ASHRREV_I64_gfx10:
+  case AMDGPU::V_ASHR_I64:
+    return 1;
+  default:
+    return 2;
+  }
+}
+
 bool AMDGPUAsmParser::usesConstantBus(const MCInst &Inst, unsigned OpIdx) {
   const MCOperand &MO = Inst.getOperand(OpIdx);
   if (MO.isImm()) {
@@ -2788,10 +2810,7 @@
   }
   ConstantBusUseCount += NumLiterals;
 
-  if (isGFX10())
-    return ConstantBusUseCount <= 2;
-
-  return ConstantBusUseCount <= 1;
+  return ConstantBusUseCount <= getConstantBusLimit(Opcode);
 }
 
 bool AMDGPUAsmParser::validateEarlyClobberLimitations(const MCInst &Inst) {