release/20.x: [SystemZ] Fix compile time regression in adjustInliningThreshold(). (#137527)

[llvmbot]

Backport 98b895d

Requested by: @JonPsson1

[llvmbot]

@uweigand What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-backend-systemz

Author: None (llvmbot)

Changes

Backport 98b895d

Requested by: @JonPsson1

---

Full diff: https://github.com/llvm/llvm-project/pull/137628.diff

1 Files Affected:

• (modified) llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp (+30-18)

diff --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
index 2b94832939419..7eec38b79cb82 100644
--- a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -18,6 +18,7 @@
 #include "llvm/CodeGen/BasicTTIImpl.h"
 #include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/InstIterator.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/Support/Debug.h"
@@ -80,7 +81,6 @@ unsigned SystemZTTIImpl::adjustInliningThreshold(const CallBase *CB) const {
   const Function *Callee = CB->getCalledFunction();
   if (!Callee)
     return 0;
-  const Module *M = Caller->getParent();
 
   // Increase the threshold if an incoming argument is used only as a memcpy
   // source.
@@ -92,25 +92,37 @@ unsigned SystemZTTIImpl::adjustInliningThreshold(const CallBase *CB) const {
     }
   }
 
-  // Give bonus for globals used much in both caller and callee.
-  std::set<const GlobalVariable *> CalleeGlobals;
-  std::set<const GlobalVariable *> CallerGlobals;
-  for (const GlobalVariable &Global : M->globals())
-    for (const User *U : Global.users())
-      if (const Instruction *User = dyn_cast<Instruction>(U)) {
-        if (User->getParent()->getParent() == Callee)
-          CalleeGlobals.insert(&Global);
-        if (User->getParent()->getParent() == Caller)
-          CallerGlobals.insert(&Global);
+  // Give bonus for globals used much in both caller and a relatively small
+  // callee.
+  unsigned InstrCount = 0;
+  SmallDenseMap<const Value *, unsigned> Ptr2NumUses;
+  for (auto &I : instructions(Callee)) {
+    if (++InstrCount == 200) {
+      Ptr2NumUses.clear();
+      break;
+    }
+    if (const auto *SI = dyn_cast<StoreInst>(&I)) {
+      if (!SI->isVolatile())
+        if (auto *GV = dyn_cast<GlobalVariable>(SI->getPointerOperand()))
+          Ptr2NumUses[GV]++;
+    } else if (const auto *LI = dyn_cast<LoadInst>(&I)) {
+      if (!LI->isVolatile())
+        if (auto *GV = dyn_cast<GlobalVariable>(LI->getPointerOperand()))
+          Ptr2NumUses[GV]++;
+    } else if (const auto *GEP = dyn_cast<GetElementPtrInst>(&I)) {
+      if (auto *GV = dyn_cast<GlobalVariable>(GEP->getPointerOperand())) {
+        unsigned NumStores = 0, NumLoads = 0;
+        countNumMemAccesses(GEP, NumStores, NumLoads, Callee);
+        Ptr2NumUses[GV] += NumLoads + NumStores;
       }
-  for (auto *GV : CalleeGlobals)
-    if (CallerGlobals.count(GV)) {
-      unsigned CalleeStores = 0, CalleeLoads = 0;
+    }
+  }
+
+  for (auto [Ptr, NumCalleeUses] : Ptr2NumUses)
+    if (NumCalleeUses > 10) {
       unsigned CallerStores = 0, CallerLoads = 0;
-      countNumMemAccesses(GV, CalleeStores, CalleeLoads, Callee);
-      countNumMemAccesses(GV, CallerStores, CallerLoads, Caller);
-      if ((CalleeStores + CalleeLoads) > 10 &&
-          (CallerStores + CallerLoads) > 10) {
+      countNumMemAccesses(Ptr, CallerStores, CallerLoads, Caller);
+      if (CallerStores + CallerLoads > 10) {
         Bonus = 1000;
         break;
       }

[uweigand]

LGTM

[github-actions]

@JonPsson1 (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.