[llvm] d9194b6 - [Attributor] Introduce a helper do deal with constant type mismatches

[Johannes Doerfert via llvm-commits]

Author: Johannes Doerfert
Date: 2021-06-18T01:07:52-05:00
New Revision: d9194b6efb4d287d2a9f2ad216a6fb5b7b260353

URL: https://github.com/llvm/llvm-project/commit/d9194b6efb4d287d2a9f2ad216a6fb5b7b260353
DIFF: https://github.com/llvm/llvm-project/commit/d9194b6efb4d287d2a9f2ad216a6fb5b7b260353.diff

LOG: [Attributor] Introduce a helper do deal with constant type mismatches

If we simplify values we sometimes end up with type mismatches. If the
value is a constant we can often cast it though to still allow
propagation. The logic is now put into a helper and it replaces some
ad hoc things we did before.

This also introduces the AA namespace for abstract attribute related
functions and types.

Differential Revision: https://reviews.llvm.org/D103856

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/Attributor.cpp
    llvm/lib/Transforms/IPO/AttributorAttributes.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 414bd2e3db8a..e8d79fd15f7e 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Analysis/MustExecute.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Attributes.h"
+#include "llvm/IR/Constants.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instruction.h"
@@ -167,6 +168,8 @@ ChangeStatus llvm::operator&(ChangeStatus L, ChangeStatus R) {
 Value *AA::getWithType(Value &V, Type &Ty) {
   if (V.getType() == &Ty)
     return &V;
+  if (isa<PoisonValue>(V))
+    return PoisonValue::get(&Ty);
   if (isa<UndefValue>(V))
     return UndefValue::get(&Ty);
   if (auto *C = dyn_cast<Constant>(&V)) {

diff  --git a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
index bb2cc3f7659d..fe5e5369a4bd 100644
--- a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -4631,10 +4631,10 @@ struct AAValueSimplifyImpl : AAValueSimplify {
     auto *C = SimplifiedAssociatedValue.hasValue()
                   ? dyn_cast<Constant>(SimplifiedAssociatedValue.getValue())
                   : UndefValue::get(V.getType());
-    if (C && C != &V) {
+    if (C && C != &V && !V.user_empty()) {
       Value *NewV = AA::getWithType(*C, *V.getType());
       // We can replace the AssociatedValue with the constant.
-      if (!V.user_empty() && &V != C && NewV) {
+      if (NewV && NewV != &V) {
         LLVM_DEBUG(dbgs() << "[ValueSimplify] " << V << " -> " << *NewV
                           << " :: " << *this << "\n");
         if (A.changeValueAfterManifest(V, *NewV))
@@ -4773,35 +4773,34 @@ struct AAValueSimplifyReturned : AAValueSimplifyImpl {
 
     if (SimplifiedAssociatedValue.hasValue() &&
         !SimplifiedAssociatedValue.getValue())
-      return Changed;
+      return Changed | AAValueSimplify::manifest(A);
 
-    Value &V = getAssociatedValue();
     auto *C = SimplifiedAssociatedValue.hasValue()
                   ? dyn_cast<Constant>(SimplifiedAssociatedValue.getValue())
-                  : UndefValue::get(V.getType());
-    if (C && C != &V) {
-      auto PredForReturned =
-          [&](Value &V, const SmallSetVector<ReturnInst *, 4> &RetInsts) {
-            // We can replace the AssociatedValue with the constant.
-            if (&V == C || isa<UndefValue>(V))
-              return true;
-
-            for (ReturnInst *RI : RetInsts) {
-              if (RI->getFunction() != getAnchorScope())
-                continue;
-              Value *NewV =
-                  AA::getWithType(*C, *RI->getReturnValue()->getType());
-              if (!NewV)
-                continue;
-              LLVM_DEBUG(dbgs() << "[ValueSimplify] " << V << " -> " << *NewV
-                                << " in " << *RI << " :: " << *this << "\n");
-              if (A.changeUseAfterManifest(RI->getOperandUse(0), *NewV))
-                Changed = ChangeStatus::CHANGED;
-            }
+                  : UndefValue::get(getAssociatedType());
+    if (!C || C == &getAssociatedValue())
+      return Changed | AAValueSimplify::manifest(A);
+
+    auto PredForReturned =
+        [&](Value &V, const SmallSetVector<ReturnInst *, 4> &RetInsts) {
+          // We can replace the AssociatedValue with the constant.
+          if (&V == C || isa<UndefValue>(V))
             return true;
-          };
-      A.checkForAllReturnedValuesAndReturnInsts(PredForReturned, *this);
-    }
+
+          for (ReturnInst *RI : RetInsts) {
+            if (RI->getFunction() != getAnchorScope())
+              continue;
+            Value *NewV = AA::getWithType(*C, *RI->getReturnValue()->getType());
+            if (!NewV)
+              continue;
+            LLVM_DEBUG(dbgs() << "[ValueSimplify] " << V << " -> " << *NewV
+                              << " in " << *RI << " :: " << *this << "\n");
+            if (A.changeUseAfterManifest(RI->getOperandUse(0), *NewV))
+              Changed = ChangeStatus::CHANGED;
+          }
+          return true;
+        };
+    A.checkForAllReturnedValuesAndReturnInsts(PredForReturned, *this);
 
     return Changed | AAValueSimplify::manifest(A);
   }