Merge branch 'master' into update-slang-rhi

docs/user-guide/03-convenience-features.md

@@ -149,7 +149,7 @@ int rs = foo.staticMethod(a,b);
 
 ### Mutability of member function
 
-For GPU performance considerations, the `this` argument in a member function is immutable by default. If you modify the content in `this` argument, the modification will be discarded after the call and does not affect the input object. If you intend to define a member function that mutates the object, use `[mutating]` attribute on the member function as shown in the following example.
+For GPU performance considerations, the `this` argument in a member function is immutable by default. Attempting to modify `this` will result in a compile error. If you intend to define a member function that mutates the object, use `[mutating]` attribute on the member function as shown in the following example.
 
 ```hlsl
 struct Foo
@@ -159,14 +159,14 @@ struct Foo
     [mutating]
     void setCount(int x) { count = x; }
 
-    void setCount2(int x) { count = x; }
+    // This would fail to compile.
+    // void setCount2(int x) { count = x; }
 }
 
 void test()
 {
     Foo f;
-    f.setCount(1); // f.count is 1 after the call.
-    f.setCount2(2); // f.count is still 1 after the call.
+    f.setCount(1); // Compiles
 }
 ```
 

source/slang/slang-ir-simplify-cfg.cpp

@@ -490,11 +490,19 @@ static bool trySimplifyIfElse(IRBuilder& builder, IRIfElse* ifElseInst)
     bool isFalseBranchTrivial = false;
     if (isTrivialIfElse(ifElseInst, isTrueBranchTrivial, isFalseBranchTrivial))
     {
-        // If both branches of `if-else` are trivial jumps into after block,
+        // If either branch of `if-else` is a trivial jump into after block,
         // we can get rid of the entire conditional branch and replace it
         // with a jump into the after block.
-        if (auto termInst = as<IRUnconditionalBranch>(ifElseInst->getTrueBlock()->getTerminator()))
+        IRUnconditionalBranch* termInst =
+            as<IRUnconditionalBranch>(ifElseInst->getTrueBlock()->getTerminator());
+        if (!termInst || (termInst->getTargetBlock() != ifElseInst->getAfterBlock()))
         {
+            termInst = as<IRUnconditionalBranch>(ifElseInst->getFalseBlock()->getTerminator());
+        }
+
+        if (termInst)
+        {
+            SLANG_ASSERT(termInst->getTargetBlock() == ifElseInst->getAfterBlock());
             List<IRInst*> args;
             for (UInt i = 0; i < termInst->getArgCount(); i++)
                 args.add(termInst->getArg(i));

tests/bugs/simplify-if-else.slang

@@ -0,0 +1,26 @@
+//TEST:SIMPLE(filecheck=CHECK): -stage compute -entry computeMain -target hlsl
+//CHECK: computeMain
+
+//TEST_INPUT:ubuffer(data=[9 9 9 9], stride=4):out,name=outputBuffer
+RWStructuredBuffer<int> outputBuffer;
+
+[numthreads(4, 1, 1)]
+void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+{
+    vector<float32_t, 4> vvv = vector<float32_t, 4>(0);
+    float32_t ret = 0.0f;
+    if (vvv.y < 1.0f)
+    {
+        ret = 1.0f;
+    }
+    else
+    {
+        if (vvv.y > 1.0f && outputBuffer[3] == 3)
+        {
+            ret = 0.0f;
+        } else {
+            if (true) {}
+        }
+    }
+    outputBuffer[int(dispatchThreadID.x)] = int(ret);
+}