[PredicateInfo] Use Intrinsic::getDeclaration now that it handles unnamed types.

This is a second attempt to fix the EXPENSIVE_CHECKS issue that was mentioned  In D91661#2875179 by @jroelofs.

(The first attempt was in D105983)

D91661 more or less completely reverted D49126 and by doing so also removed the cleanup logic of the created declarations and calls.
This patch is a replacement for D91661 (which must itself be reverted first). It replaces the custom declaration creation with the
generic version and shows the test impact. It also tracks the number of NamedValues to detect if a new prototype was added instead
of looking at the available users of a prototype.

Reviewed By: jroelofs

Differential Revision: https://reviews.llvm.org/D106147

1 files changed, 13 insertions, 19 deletions

diff --git a/llvm/lib/Transforms/Utils/PredicateInfo.cpp b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
index 4c262f6..bd2b6fa 100644
--- a/llvm/lib/Transforms/Utils/PredicateInfo.cpp
+++ b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
@@ -539,21 +539,6 @@ void PredicateInfoBuilder::buildPredicateInfo() {
   renameUses(OpsToRename);
 }
 
-// Create a ssa_copy declaration with custom mangling, because
-// Intrinsic::getDeclaration does not handle overloaded unnamed types properly:
-// all unnamed types get mangled to the same string. We use the pointer
-// to the type as name here, as it guarantees unique names for different
-// types and we remove the declarations when destroying PredicateInfo.
-// It is a workaround for PR38117, because solving it in a fully general way is
-// tricky (FIXME).
-static Function *getCopyDeclaration(Module *M, Type *Ty) {
-  std::string Name = "llvm.ssa.copy." + utostr((uintptr_t) Ty);
-  return cast<Function>(
-      M->getOrInsertFunction(Name,
-                             getType(M->getContext(), Intrinsic::ssa_copy, Ty))
-          .getCallee());
-}
-
 // Given the renaming stack, make all the operands currently on the stack real
 // by inserting them into the IR.  Return the last operation's value.
 Value *PredicateInfoBuilder::materializeStack(unsigned int &Counter,
@@ -583,10 +568,17 @@ Value *PredicateInfoBuilder::materializeStack(unsigned int &Counter,
     // to ensure we dominate all of our uses.  Always insert right before the
     // relevant instruction (terminator, assume), so that we insert in proper
     // order in the case of multiple predicateinfo in the same block.
+    // The number of named values is used to detect if a new declaration was
+    // added. If so, that declaration is tracked so that it can be removed when
+    // the analysis is done. The corner case were a new declaration results in
+    // a name clash and the old name being renamed is not considered as that
+    // represents an invalid module.
     if (isa<PredicateWithEdge>(ValInfo)) {
       IRBuilder<> B(getBranchTerminator(ValInfo));
-      Function *IF = getCopyDeclaration(F.getParent(), Op->getType());
-      if (IF->users().empty())
+      auto NumDecls = F.getParent()->getNumNamedValues();
+      Function *IF = Intrinsic::getDeclaration(
+          F.getParent(), Intrinsic::ssa_copy, Op->getType());
+      if (NumDecls != F.getParent()->getNumNamedValues())
         PI.CreatedDeclarations.insert(IF);
       CallInst *PIC =
           B.CreateCall(IF, Op, Op->getName() + "." + Twine(Counter++));
@@ -599,8 +591,10 @@ Value *PredicateInfoBuilder::materializeStack(unsigned int &Counter,
       // Insert the predicate directly after the assume. While it also holds
       // directly before it, assume(i1 true) is not a useful fact.
       IRBuilder<> B(PAssume->AssumeInst->getNextNode());
-      Function *IF = getCopyDeclaration(F.getParent(), Op->getType());
-      if (IF->users().empty())
+      auto NumDecls = F.getParent()->getNumNamedValues();
+      Function *IF = Intrinsic::getDeclaration(
+          F.getParent(), Intrinsic::ssa_copy, Op->getType());
+      if (NumDecls != F.getParent()->getNumNamedValues())
         PI.CreatedDeclarations.insert(IF);
       CallInst *PIC = B.CreateCall(IF, Op);
       PI.PredicateMap.insert({PIC, ValInfo});