4 files changed, 36 insertions, 7 deletions

diff --git a/source/slang/slang-emit-c-like.cpp b/source/slang/slang-emit-c-like.cpp
index 25dff6083..bd3337769 100644
--- a/source/slang/slang-emit-c-like.cpp
+++ b/source/slang/slang-emit-c-like.cpp
@@ -639,6 +639,35 @@ bool CLikeSourceEmitter::maybeEmitParens(EmitOpInfo& outerPrec, const EmitOpInfo
     bool needParens = (prec.leftPrecedence <= outerPrec.leftPrecedence)
         || (prec.rightPrecedence <= outerPrec.rightPrecedence);
 
+    // While Slang correctly removes some of parentheses, DXC prints warnings
+    // for common mistakes when parentheses are not used with certain combinations
+    // of the operations. We emit parentheses to avoid the warnings.
+    //
+    // a | b & c => a | (b & c)
+    if (prec.leftPrecedence == EPrecedence::kEPrecedence_BitAnd_Left
+        && outerPrec.leftPrecedence == EPrecedence::kEPrecedence_BitOr_Right)
+    {
+        needParens = true;
+    }
+    // a & b | c => (a & b) | c
+    else if (prec.rightPrecedence == EPrecedence::kEPrecedence_BitAnd_Right
+        && outerPrec.rightPrecedence == EPrecedence::kEPrecedence_BitOr_Left)
+    {
+        needParens = true;
+    }
+    // a << b + c => a << (b + c)
+    else if (prec.leftPrecedence == EPrecedence::kEPrecedence_Additive_Left
+        && outerPrec.leftPrecedence == EPrecedence::kEPrecedence_Shift_Right)
+    {
+        needParens = true;
+    }
+    // a + b << c => (a + b) << c
+    else if (prec.rightPrecedence == EPrecedence::kEPrecedence_Additive_Right
+        && outerPrec.rightPrecedence == EPrecedence::kEPrecedence_Shift_Left)
+    {
+        needParens = true;
+    }
+
     if (needParens)
     {
         m_writer->emit("(");
@@ -2305,7 +2334,7 @@ void CLikeSourceEmitter::defaultEmitInstExpr(IRInst* inst, const EmitOpInfo& inO
             }
         }
 
-        emitOperand(operand, rightSide(prec, outerPrec));
+        emitOperand(operand, rightSide(outerPrec, prec));
         break;
     }    
     case kIROp_Load:
@@ -2455,7 +2484,7 @@ void CLikeSourceEmitter::defaultEmitInstExpr(IRInst* inst, const EmitOpInfo& inO
         needClose = maybeEmitParens(outerPrec, prec);
         emitOperand(inst->getOperand(0), leftSide(outerPrec, prec));
         m_writer->emit(" + ");
-        emitOperand(inst->getOperand(1), rightSide(prec, outerPrec));
+        emitOperand(inst->getOperand(1), rightSide(outerPrec, prec));
         break;
     }
     case kIROp_GetElement:
@@ -2472,7 +2501,7 @@ void CLikeSourceEmitter::defaultEmitInstExpr(IRInst* inst, const EmitOpInfo& inO
             m_writer->emit("[");
             emitOperand(inst->getOperand(1), getInfo(EmitOp::General));
             m_writer->emit("].");
-            emitOperand(inst->getOperand(0), rightSide(prec, outerPrec));
+            emitOperand(inst->getOperand(0), rightSide(outerPrec, prec));
             break;
         }
         else
@@ -2558,7 +2587,7 @@ void CLikeSourceEmitter::defaultEmitInstExpr(IRInst* inst, const EmitOpInfo& inO
             m_writer->emit(" ? ");
             emitOperand(inst->getOperand(1), prec);
             m_writer->emit(" : ");
-            emitOperand(inst->getOperand(2), rightSide(prec, outerPrec));
+            emitOperand(inst->getOperand(2), rightSide(outerPrec, prec));
         }
         break;
 
diff --git a/source/slang/slang-emit-glsl.cpp b/source/slang/slang-emit-glsl.cpp
index 293bcb891..32301c418 100644
--- a/source/slang/slang-emit-glsl.cpp
+++ b/source/slang/slang-emit-glsl.cpp
@@ -2064,7 +2064,7 @@ bool GLSLSourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inOu
             }
 
             m_writer->emit(" = ");
-            emitOperand(inst->getOperand(2), rightSide(assignPrec, outerPrec));
+            emitOperand(inst->getOperand(2), rightSide(outerPrec, assignPrec));
             maybeCloseParens(assignNeedsClose);
             return true;
         }
diff --git a/source/slang/slang-emit-metal.cpp b/source/slang/slang-emit-metal.cpp
index 17d074e75..bf4a67b09 100644
--- a/source/slang/slang-emit-metal.cpp
+++ b/source/slang/slang-emit-metal.cpp
@@ -283,7 +283,7 @@ bool MetalSourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inO
             needClose = maybeEmitParens(outerPrec, prec);
             emitOperand(inst->getOperand(0), leftSide(outerPrec, prec));
             m_writer->emit("+");
-            emitOperand(inst->getOperand(1), rightSide(prec, outerPrec));
+            emitOperand(inst->getOperand(1), rightSide(outerPrec, prec));
             maybeCloseParens(needClose);
             return true;
         }
diff --git a/source/slang/slang-emit-precedence.h b/source/slang/slang-emit-precedence.h
index 1c8081079..f23287bcb 100644
--- a/source/slang/slang-emit-precedence.h
+++ b/source/slang/slang-emit-precedence.h
@@ -143,7 +143,7 @@ SLANG_INLINE EmitOpInfo leftSide(EmitOpInfo const& outerPrec, EmitOpInfo const&
     return result;
 }
 
-SLANG_INLINE EmitOpInfo rightSide(EmitOpInfo const& prec, EmitOpInfo const& outerPrec)
+SLANG_INLINE EmitOpInfo rightSide(EmitOpInfo const& outerPrec, EmitOpInfo const& prec)
 {
     EmitOpInfo result;
     result.op = nullptr;