More control flow simplifications. (#2673)

* More control flow and Phi param simplifications.

* Fix.

* Fix gcc error.

* Fix.

* More IR cleanup.

* Fix bug in phi param dce + ifelse simplify.

* Propagate and DCE side-effect-free functions.

* Enhance CFG simplifcation to remove loops with no side effects.

* Fix.

* Fixes.

* Fix tests. Add [__AlwaysFoldIntoUseSite] for rayPayloadLocation.

* More cleanup.

* Fixes.

* Fix.

---------

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/source/slang/slang-ir-ssa-simplification.cpp b/source/slang/slang-ir-ssa-simplification.cpp
index f06fafcb3..beaaae065 100644
--- a/source/slang/slang-ir-ssa-simplification.cpp
+++ b/source/slang/slang-ir-ssa-simplification.cpp
@@ -10,6 +10,7 @@
 #include "slang-ir-deduplicate-generic-children.h"
 #include "slang-ir-remove-unused-generic-param.h"
 #include "slang-ir-redundancy-removal.h"
+#include "slang-ir-propagate-func-properties.h"
 
 namespace Slang
 {
@@ -29,6 +30,7 @@ namespace Slang
             changed |= peepholeOptimize(module);
             changed |= removeRedundancy(module);
             changed |= simplifyCFG(module);
+            changed |= propagateFuncProperties(module);
 
             // Note: we disregard the `changed` state from dead code elimination pass since
             // SCCP pass could be generating temporarily evaluated constant values and never actually use them.
@@ -41,6 +43,28 @@ namespace Slang
         }
     }
 
+    void simplifyNonSSAIR(IRModule* module)
+    {
+        bool changed = true;
+        const int kMaxIterations = 8;
+        int iterationCounter = 0;
+        while (changed && iterationCounter < kMaxIterations)
+        {
+            changed = false;
+            changed |= peepholeOptimize(module);
+            changed |= removeRedundancy(module);
+            changed |= simplifyCFG(module);
+
+            // Note: we disregard the `changed` state from dead code elimination pass since
+            // SCCP pass could be generating temporarily evaluated constant values and never actually use them.
+            // DCE will always remove those nearly generated consts and always returns true here.
+            eliminateDeadCode(module);
+
+            iterationCounter++;
+        }
+    }
+
+
     void simplifyFunc(IRGlobalValueWithCode* func)
     {
         bool changed = true;