IROutliner: Use ValueMapper to remap constants in a function

[arsenm]

Stop relying on the uselist of constants, which also required filtering
the uses that are in the correct function. I'm not sure why this pass is
doing its own cloning instead of building the value map while doing its
cloning.

[arsenm]

• IROutliner: Do not look at use lists of constant phi inputs #135019
• IROutliner: Use ValueMapper to remap constants in a function #134850 👈 (View in Graphite)
• main

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[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Matt Arsenault (arsenm)

Changes

Stop relying on the uselist of constants, which also required filtering
the uses that are in the correct function. I'm not sure why this pass is
doing its own cloning instead of building the value map while doing its
cloning.

---

Full diff: https://github.com/llvm/llvm-project/pull/134850.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/IPO/IROutliner.cpp (+9-8)

diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
index fd76d3a32049c..7e9ec4a04d5e3 100644
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -24,6 +24,7 @@
 #include "llvm/IR/PassManager.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/Utils/ValueMapper.h"
 #include <optional>
 #include <vector>
 
@@ -1930,10 +1931,12 @@ replaceArgumentUses(OutlinableRegion &Region,
 /// \param Region [in] - The region of extracted code to be changed.
 void replaceConstants(OutlinableRegion &Region) {
   OutlinableGroup &Group = *Region.Parent;
+  Function *OutlinedFunction = Group.OutlinedFunction;
+  ValueToValueMapTy VMap;
+
   // Iterate over the constants that need to be elevated into arguments
   for (std::pair<unsigned, Constant *> &Const : Region.AggArgToConstant) {
     unsigned AggArgIdx = Const.first;
-    Function *OutlinedFunction = Group.OutlinedFunction;
     assert(OutlinedFunction && "Overall Function is not defined?");
     Constant *CST = Const.second;
     Argument *Arg = Group.OutlinedFunction->getArg(AggArgIdx);
@@ -1943,16 +1946,14 @@ void replaceConstants(OutlinableRegion &Region) {
     // TODO: If in the future constants do not have one global value number,
     // i.e. a constant 1 could be mapped to several values, this check will
     // have to be more strict.  It cannot be using only replaceUsesWithIf.
-
+    VMap[CST] = Arg;
     LLVM_DEBUG(dbgs() << "Replacing uses of constant " << *CST
                       << " in function " << *OutlinedFunction << " with "
-                      << *Arg << "\n");
-    CST->replaceUsesWithIf(Arg, [OutlinedFunction](Use &U) {
-      if (Instruction *I = dyn_cast<Instruction>(U.getUser()))
-        return I->getFunction() == OutlinedFunction;
-      return false;
-    });
+                      << *Arg << '\n');
   }
+
+  RemapFunction(*OutlinedFunction, VMap,
+                RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
 }
 
 /// It is possible that there is a basic block that already performs the same

[arsenm]

Merge activity

• Apr 10, 4:29 PM EDT: A user started a stack merge that includes this pull request via Graphite.
• Apr 10, 4:31 PM EDT: A user merged this pull request with Graphite.