[llvm] 1d0476c - [FuncSpec] Prefer DataLayout-aware constant folding of GEPs.

[Alexandros Lamprineas via llvm-commits]

Author: Alexandros Lamprineas
Date: 2023-07-11T13:24:26+01:00
New Revision: 1d0476cb4d152872d7df20eb3330d9e53fff5a3a

URL: https://github.com/llvm/llvm-project/commit/1d0476cb4d152872d7df20eb3330d9e53fff5a3a
DIFF: https://github.com/llvm/llvm-project/commit/1d0476cb4d152872d7df20eb3330d9e53fff5a3a.diff

LOG: [FuncSpec] Prefer DataLayout-aware constant folding of GEPs.

As shown in D154820, the DataLayout-independent constant folding
interface is not good enough for handling GEPs. Instead we should
be using the DataLayout-aware constant folding interface. Since
there isn't a method to specifically handle GEPs we can use the
one which folds generic instruction operands.

Differential Revision: https://reviews.llvm.org/D154821

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
    llvm/unittests/Transforms/IPO/FunctionSpecializationTest.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp b/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
index 5180e3ffa09777..b51b45a8fb16ea 100644
--- a/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionSpecialization.cpp
@@ -55,7 +55,6 @@
 #include "llvm/Analysis/ValueLattice.h"
 #include "llvm/Analysis/ValueLatticeUtils.h"
 #include "llvm/Analysis/ValueTracking.h"
-#include "llvm/IR/ConstantFold.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/Transforms/Scalar/SCCP.h"
 #include "llvm/Transforms/Utils/Cloning.h"
@@ -260,7 +259,7 @@ Constant *InstCostVisitor::visitLoadInst(LoadInst &I) {
 }
 
 Constant *InstCostVisitor::visitGetElementPtrInst(GetElementPtrInst &I) {
-  SmallVector<Value *, 8> Operands;
+  SmallVector<Constant *, 8> Operands;
   Operands.reserve(I.getNumOperands());
 
   for (unsigned Idx = 0, E = I.getNumOperands(); Idx != E; ++Idx) {
@@ -273,10 +272,8 @@ Constant *InstCostVisitor::visitGetElementPtrInst(GetElementPtrInst &I) {
     Operands.push_back(C);
   }
 
-  auto *Ptr = cast<Constant>(Operands[0]);
-  auto Ops = ArrayRef(Operands.begin() + 1, Operands.end());
-  return ConstantFoldGetElementPtr(I.getSourceElementType(), Ptr,
-                                   I.isInBounds(), std::nullopt, Ops);
+  auto Ops = ArrayRef(Operands.begin(), Operands.end());
+  return ConstantFoldInstOperands(&I, Ops, DL);
 }
 
 Constant *InstCostVisitor::visitSelectInst(SelectInst &I) {

diff  --git a/llvm/unittests/Transforms/IPO/FunctionSpecializationTest.cpp b/llvm/unittests/Transforms/IPO/FunctionSpecializationTest.cpp
index 12e5d98d516203..222311dc040a86 100644
--- a/llvm/unittests/Transforms/IPO/FunctionSpecializationTest.cpp
+++ b/llvm/unittests/Transforms/IPO/FunctionSpecializationTest.cpp
@@ -281,8 +281,8 @@ TEST_F(FunctionSpecializationTest, Misc) {
   Ref = getInstCost(Gep) + getInstCost(Load) + getInstCost(Freeze) +
         getInstCost(Smax);
   Bonus = Specializer.getSpecializationBonus(F->getArg(2), GV, Visitor);
-  EXPECT_NE(Bonus, Ref);
-  EXPECT_FALSE(Bonus > 0);
+  EXPECT_EQ(Bonus, Ref);
+  EXPECT_TRUE(Bonus > 0);
 
   Bonus = Specializer.getSpecializationBonus(F->getArg(3), Undef, Visitor);
   EXPECT_TRUE(Bonus == 0);