[Analysis] Centralize objectsize lowering logic.

We're currently doing nearly the same thing for @llvm.objectsize in
three different places: two of them are missing checks for overflow,
and one of them could subtly break if InstCombine gets much smarter
about removing alloc sites. Seems like a good idea to not do that.

llvm-svn: 290214

2 files changed, 8 insertions, 16 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 4d432d56aa3..eb5c63433e7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1440,17 +1440,12 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
 
   switch (II->getIntrinsicID()) {
   default: break;
-  case Intrinsic::objectsize: {
-    uint64_t Size;
-    if (getObjectSize(II->getArgOperand(0), Size, DL, &TLI)) {
-      APInt APSize(II->getType()->getIntegerBitWidth(), Size);
-      // Equality check to be sure that `Size` can fit in a value of type
-      // `II->getType()`
-      if (APSize == Size)
-        return replaceInstUsesWith(CI, ConstantInt::get(II->getType(), APSize));
-    }
+  case Intrinsic::objectsize:
+    if (ConstantInt *N =
+            lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/false))
+      return replaceInstUsesWith(CI, N);
     return nullptr;
-  }
+
   case Intrinsic::bswap: {
     Value *IIOperand = II->getArgOperand(0);
     Value *X = nullptr;
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 0d29c1dceea..9a52874c4c2 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2027,12 +2027,9 @@ Instruction *InstCombiner::visitAllocSite(Instruction &MI) {
 
       if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
         if (II->getIntrinsicID() == Intrinsic::objectsize) {
-          uint64_t Size;
-          if (!getObjectSize(II->getArgOperand(0), Size, DL, &TLI)) {
-            ConstantInt *CI = cast<ConstantInt>(II->getArgOperand(1));
-            Size = CI->isZero() ? -1ULL : 0;
-          }
-          replaceInstUsesWith(*I, ConstantInt::get(I->getType(), Size));
+          ConstantInt *Result = lowerObjectSizeCall(II, DL, &TLI,
+                                                    /*MustSucceed=*/true);
+          replaceInstUsesWith(*I, Result);
           eraseInstFromFunction(*I);
           Users[i] = nullptr; // Skip examining in the next loop.
         }