Fold constant compares and better loop detection

dotnet · Jun 21, 2022 · 84f2ef4 · 84f2ef4
1 parent 34989bb
commit 84f2ef4
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Showing 2 changed files with 10 additions and 9 deletions.
diff --git a/src/coreclr/jit/gentree.cpp b/src/coreclr/jit/gentree.cpp
@@ -12949,6 +12949,12 @@ GenTree* Compiler::gtFoldExprConditional(GenTree* tree)
         DISPTREE(replacement);
         JITDUMP("\n");
 
+        // If we bashed to a compare, try to fold that.
+        if (replacement->OperIsCompare())
+        {
+            return gtFoldExprCompare(replacement);
+        }
+
         return replacement;
     }
 

diff --git a/src/coreclr/jit/optimizer.cpp b/src/coreclr/jit/optimizer.cpp
@@ -4499,17 +4499,12 @@ bool Compiler::optIfConvert(BasicBlock* block)
 // Arm only for now.
 #ifdef TARGET_ARM64
 
-    // Don't optimise the block if it is inside a loop.
+    // Don't optimise the block if it is inside a loop
     // When inside a loop, branches are quicker than selects.
-    if (fgHasLoops)
+    // Detect via the block weight as that will be high when inside a loop.
+    if (block->getBBWeight(this) > BB_UNITY_WEIGHT)
     {
-        for (unsigned loopNum = 0; loopNum < optLoopCount; loopNum++)
-        {
-            if (optLoopTable[loopNum].lpContains(block))
-            {
-                return false;
-            }
-        }
+        return false;
     }
 
     // Does the block end by branching via a JTRUE after a compare?