Fix regression in float to bool conversion. (#6497)

Author: csyonghe

source/slang/slang-ir.cpp

@@ -4047,7 +4047,7 @@ IRInst* IRBuilder::emitCast(IRType* type, IRInst* value, bool fallbackToBuiltinC
         /* From Float */
         {kIROp_CastFloatToInt,
          kIROp_FloatCast,
-         {kIROp_CastFloatToInt, kIROp_IntCast},
+         {kIROp_Neq},
          {kIROp_CastFloatToInt, kIROp_CastIntToPtr},
          kIROp_CastToVoid},
         /* From Bool  */
@@ -4079,6 +4079,13 @@ IRInst* IRBuilder::emitCast(IRType* type, IRInst* value, bool fallbackToBuiltinC
                 matType->getColumnCount(),
                 matType->getLayout());
     }
+
+    if (op.op0 == kIROp_Neq)
+    {
+        IRInst* args[2] = {value, emitDefaultConstruct(value->getDataType())};
+        return emitIntrinsicInst(type, op.op0, 2, args);
+    }
+
     auto result = emitIntrinsicInst(t, op.op0, 1, &value);
     if (op.op1 != kIROp_Nop)
     {

tests/bugs/float-to-bool.slang

@@ -0,0 +1,25 @@
+//TEST:COMPARE_COMPUTE(filecheck-buffer=CHECK): -xslang -Wno-30081
+//TEST:COMPARE_COMPUTE(filecheck-buffer=CHECK): -vk -xslang -Wno-30081
+
+//TEST_INPUT: set outputBuffer = out ubuffer(data=[0 0 0 0 0], stride = 4)
+RWStructuredBuffer<int> outputBuffer;
+
+//TEST_INPUT: set inputBuffer = ubuffer(data=[0.0 0.2 1.0 1.2], stride = 4)
+RWStructuredBuffer<float4> inputBuffer;
+[numthreads(1,1,1)]
+void computeMain()
+{
+    bool4 bv = inputBuffer[0];
+    outputBuffer[0] = bv.x;
+    outputBuffer[1] = bv.y;
+    outputBuffer[2] = bv.z;
+    outputBuffer[3] = bv.w;
+    bool b = inputBuffer[0].y;
+    outputBuffer[4] = b;
+}
+
+// CHECK: 0
+// CHECK: 1
+// CHECK: 1
+// CHECK: 1
+// CHECK: 1