[CodeGen] Avoid repeated hash lookups (NFC) (#126852)

kazutakahirata · web-flow · commit 71cceb1439c1 · 2025-02-12T08:45:53.000-08:00
diff --git a/llvm/include/llvm/CodeGen/MachinePipeliner.h b/llvm/include/llvm/CodeGen/MachinePipeliner.h
@@ -468,9 +468,10 @@ class NodeSet {
         SUnit *SuccSUnit = Succ.getDst();
         if (V != SuccSUnit)
           continue;
-        if (SUnitToDistance[U] + Succ.getLatency() > SUnitToDistance[V]) {
-          SUnitToDistance[V] = SUnitToDistance[U] + Succ.getLatency();
-        }
+        unsigned &DU = SUnitToDistance[U];
+        unsigned &DV = SUnitToDistance[V];
+        if (DU + Succ.getLatency() > DV)
+          DV = DU + Succ.getLatency();
       }
     }
     // Handle a back-edge in loop carried dependencies

Original file line number	Diff line number	Diff line change
`@@ -468,9 +468,10 @@ class NodeSet {`
`468`	`468`	`SUnit *SuccSUnit = Succ.getDst();`
`469`	`469`	`if (V != SuccSUnit)`
`470`	`470`	`continue;`
`471`		`- if (SUnitToDistance[U] + Succ.getLatency() > SUnitToDistance[V]) {`
`472`		`- SUnitToDistance[V] = SUnitToDistance[U] + Succ.getLatency();`
`473`		`- }`
	`471`	`+ unsigned &DU = SUnitToDistance[U];`
	`472`	`+ unsigned &DV = SUnitToDistance[V];`
	`473`	`+ if (DU + Succ.getLatency() > DV)`
	`474`	`+ DV = DU + Succ.getLatency();`
`474`	`475`	`}`
`475`	`476`	`}`
`476`	`477`	`// Handle a back-edge in loop carried dependencies`