[llvm] r330752 - [AMDGPU] Truncate packed inline constant

[Stanislav Mekhanoshin via llvm-commits]

Author: rampitec
Date: Tue Apr 24 11:17:55 2018
New Revision: 330752

URL: http://llvm.org/viewvc/llvm-project?rev=330752&view=rev
Log:
[AMDGPU] Truncate packed inline constant

If a packed inline constant is sign extended it must be truncated
after the shift. I.e. a constant (0xH0000, 0xHBC00), will be represented
as 0xFFFFFFFFBC000000 in the IR because the immediate is sign extended
to 64 bit. After the value shifted right by 16 to use it in a low part
with op_sel_hi it becomes 0xFFFFFFFFBC00 and does not qualify as inline
constant any longer.

Fixed the error and added verification code. Without the fix and with
the verification bug is causing pk_max_f16_literal.ll to fail.

Differential Revision: https://reviews.llvm.org/D45987

Modified:
    llvm/trunk/lib/Target/AMDGPU/SIFoldOperands.cpp
    llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
    llvm/trunk/test/CodeGen/AMDGPU/pk_max_f16_literal.ll

Modified: llvm/trunk/lib/Target/AMDGPU/SIFoldOperands.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIFoldOperands.cpp?rev=330752&r1=330751&r2=330752&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIFoldOperands.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIFoldOperands.cpp Tue Apr 24 11:17:55 2018
@@ -178,7 +178,7 @@ static bool updateOperand(FoldCandidate
         if (!(Fold.ImmToFold & 0xffff)) {
           Mod.setImm(Mod.getImm() | SISrcMods::OP_SEL_0);
           Mod.setImm(Mod.getImm() & ~SISrcMods::OP_SEL_1);
-          Old.ChangeToImmediate(Fold.ImmToFold >> 16);
+          Old.ChangeToImmediate((Fold.ImmToFold >> 16) & 0xffff);
           return true;
         }
         Mod.setImm(Mod.getImm() & ~SISrcMods::OP_SEL_1);

Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp?rev=330752&r1=330751&r2=330752&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp Tue Apr 24 11:17:55 2018
@@ -2725,6 +2725,7 @@ bool SIInstrInfo::verifyInstruction(cons
     const int OpIndices[] = { Src0Idx, Src1Idx, Src2Idx };
 
     unsigned ConstantBusCount = 0;
+    unsigned LiteralCount = 0;
 
     if (AMDGPU::getNamedOperandIdx(Opcode, AMDGPU::OpName::imm) != -1)
       ++ConstantBusCount;
@@ -2744,6 +2745,7 @@ bool SIInstrInfo::verifyInstruction(cons
           SGPRUsed = MO.getReg();
         } else {
           ++ConstantBusCount;
+          ++LiteralCount;
         }
       }
     }
@@ -2751,6 +2753,11 @@ bool SIInstrInfo::verifyInstruction(cons
       ErrInfo = "VOP* instruction uses the constant bus more than once";
       return false;
     }
+
+    if (isVOP3(MI) && LiteralCount) {
+      ErrInfo = "VOP3 instruction uses literal";
+      return false;
+    }
   }
 
   // Verify misc. restrictions on specific instructions.

Modified: llvm/trunk/test/CodeGen/AMDGPU/pk_max_f16_literal.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/pk_max_f16_literal.ll?rev=330752&r1=330751&r2=330752&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AMDGPU/pk_max_f16_literal.ll (original)
+++ llvm/trunk/test/CodeGen/AMDGPU/pk_max_f16_literal.ll Tue Apr 24 11:17:55 2018
@@ -40,7 +40,7 @@ bb:
 }
 
 ; GCN-LABEL: {{^}}test_pk_max_f16_literal_0_m1:
-; GFX9: v_pk_max_f16 v{{[0-9]+}}, -1.0, v{{[0-9]+}} op_sel:[1,0] op_sel_hi:[0,1]{{$}}
+; GFX9: v_pk_max_f16 v{{[0-9]+}}, v{{[0-9]+}}, -1.0 op_sel:[0,1] op_sel_hi:[1,0]{{$}}
 define amdgpu_kernel void @test_pk_max_f16_literal_0_m1(<2 x half> addrspace(1)* nocapture %arg) {
 bb:
   %tmp = tail call i32 @llvm.amdgcn.workitem.id.x()