* Fix for unary - on glsl (#1222)

* Test to check fix

3 files changed, 39 insertions, 9 deletions

diff --git a/source/slang/slang-emit-c-like.cpp b/source/slang/slang-emit-c-like.cpp
index 2212cf9cc..5f784cba3 100644
--- a/source/slang/slang-emit-c-like.cpp
+++ b/source/slang/slang-emit-c-like.cpp
@@ -1967,19 +1967,31 @@ void CLikeSourceEmitter::defaultEmitInstExpr(IRInst* inst, const EmitOpInfo& inO
 
         needClose = maybeEmitParens(outerPrec, prec);
 
-        // If it's a BitNot, but the data type is bool special case to !
-        if (emitOp == EmitOp::BitNot && as<IRBoolType>(inst->getDataType()))
+        switch (inst->op)
         {
-            m_writer->emit("!");
-        }
-        else
-        {
-            m_writer->emit(prec.op);
+            case kIROp_BitNot:
+            {
+                // If it's a BitNot, but the data type is bool special case to !
+                m_writer->emit(as<IRBoolType>(inst->getDataType()) ? "!" : prec.op);
+                break;
+            }
+            case kIROp_Not:
+            {
+                m_writer->emit(prec.op);
+                break;
+            }
+            case kIROp_Neg:
+            {
+                // Emit a space after the unary -, so if we are followed by a negative literal we don't end up with --
+                // which some downstream compilers determine to be decrement.
+                m_writer->emit("- ");
+                break;
+            }
         }
-        
+
         emitOperand(operand, rightSide(prec, outerPrec));
         break;
-    }
+    }    
     case kIROp_Load:
         {
             auto base = inst->getOperand(0);
diff --git a/tests/bugs/negative-literal.slang b/tests/bugs/negative-literal.slang
new file mode 100644
index 000000000..586cd601c
--- /dev/null
+++ b/tests/bugs/negative-literal.slang
@@ -0,0 +1,14 @@
+//TEST(compute):COMPARE_COMPUTE_EX:-cpu -compute -compile-arg -O3
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute
+//TEST(compute):COMPARE_COMPUTE_EX:-slang -compute -dx12
+//TEST(compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute
+
+//TEST_INPUT:ubuffer(data=[0 0 0 0], stride=4):out,name outputBuffer
+RWStructuredBuffer<float> outputBuffer;
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    float v = asfloat((int(dispatchThreadID.x) & -2147483648) | 1065353216);
+	outputBuffer[dispatchThreadID.x] = v;
+}
diff --git a/tests/bugs/negative-literal.slang.expected.txt b/tests/bugs/negative-literal.slang.expected.txt
new file mode 100644
index 000000000..cc5e55ab6
--- /dev/null
+++ b/tests/bugs/negative-literal.slang.expected.txt
@@ -0,0 +1,4 @@
+3F800000
+3F800000
+3F800000
+3F800000