- Enforce immediate value constraint for inline asm.

- Fixed a bug where the source of an inline asm call with multiple outputs was not being matched in PatternMatchPass.
- Fixed an issue where LLVM promotes a variable to a constant, causing an immediate value to be written to the asm string when it should not be.

__asm__ ("mov (M1, 16) %0(0,0)<1> %1(0,0)<1;1,0>" : "=rw" (s1) : "rw" (s2) );

When s2 is promoted to a constant value, the following vISA instruction is generated. The immediate value still contains the regioning info from the user inlined string.
mov (M1, 16) V39(0,0)<1> 0x3f800000:f(0,0)<1;1,0>

By enforcing the constraint, if we detect an immediate value with the "rw" constraint, we can generate an extra move instruction to resolve this issue.

Change-Id: I6421d88b41bad8fa2915e03ccab759b1eb02428c

Author: dlei6g

IGC/Compiler/CISACodeGen/EmitVISAPass.cpp

@@ -8140,6 +8140,8 @@ void EmitPass::EmitInlineAsm(llvm::CallInst* inst)
         opnds.push_back(cv);
     }
 
+    assert(opnds.size() == constraints.size());
+
     // Check for read/write registers
     if (!inst->getType()->isVoidTy())
     {
@@ -8160,6 +8162,20 @@ void EmitPass::EmitInlineAsm(llvm::CallInst* inst)
         }
     }
 
+    // Special handling if LLVM replaces a variable with an immediate, we need to insert an extra move
+    for (unsigned i = 0; i < opnds.size(); i++)
+    {
+        CVariable* opVar = opnds[i];
+        StringRef constraint = constraints[i];
+        if (opVar->IsImmediate() && !constraint.equals("i"))
+        {
+            CVariable* tempMov = m_currShader->GetNewVariable(1, opVar->GetType(), EALIGN_GRF, true);
+            m_encoder->Copy(tempMov, opVar);
+            m_encoder->Push();
+            opnds[i] = tempMov;
+        }
+    }
+
     str << endl << "/// Inlined ASM" << endl;
     // Look for variables to replace with the VISA variable
     size_t startPos = 0;

IGC/Compiler/CISACodeGen/PatternMatchPass.cpp

@@ -1349,18 +1349,20 @@ namespace IGC
         bool Match = false;
 
         // Ignore the extract value instruction. Handled in the call inst.
-        bool isExtractFromInlineAsm = false;
         if (CallInst * call = dyn_cast<CallInst>(I.getOperand(0)))
         {
-            isExtractFromInlineAsm = call->isInlineAsm() && call->getType()->isStructTy();
+            if (call->isInlineAsm() && call->getType()->isStructTy())
+            {
+                MarkAsSource(call);
+                return;
+            }
         }
 
-        Match = isExtractFromInlineAsm ||
-            MatchCopyFromStruct(&I) ||
-            matchAddPair(&I) ||
+        Match = matchAddPair(&I) ||
             matchSubPair(&I) ||
             matchMulPair(&I) ||
-            matchPtrToPair(&I);
+            matchPtrToPair(&I) ||
+            MatchCopyFromStruct(&I);
 
         assert(Match && "Unknown `extractvalue` instruction!");
     }