[llvm] 8391f40 - [InstCombine] Avoid uses of ConstantExpr::getLShr()

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-11-10T15:50:42+01:00
New Revision: 8391f405cb9cceb32abc76acf2aa47251a0da173

URL: https://github.com/llvm/llvm-project/commit/8391f405cb9cceb32abc76acf2aa47251a0da173
DIFF: https://github.com/llvm/llvm-project/commit/8391f405cb9cceb32abc76acf2aa47251a0da173.diff

LOG: [InstCombine] Avoid uses of ConstantExpr::getLShr()

Use the constant folding API instead.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
    llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index c59cf5a2a86ef44..9f59fb0939a3229 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -2132,9 +2132,12 @@ static bool collectInsertionElements(Value *V, unsigned Shift,
     Type *ElementIntTy = IntegerType::get(C->getContext(), ElementSize);
 
     for (unsigned i = 0; i != NumElts; ++i) {
-      unsigned ShiftI = Shift+i*ElementSize;
-      Constant *Piece = ConstantExpr::getLShr(C, ConstantInt::get(C->getType(),
-                                                                  ShiftI));
+      unsigned ShiftI = Shift + i * ElementSize;
+      Constant *Piece = ConstantFoldBinaryInstruction(
+          Instruction::LShr, C, ConstantInt::get(C->getType(), ShiftI));
+      if (!Piece)
+        return false;
+
       Piece = ConstantExpr::getTrunc(Piece, ElementIntTy);
       if (!collectInsertionElements(Piece, ShiftI, Elements, VecEltTy,
                                     isBigEndian))

diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
index e178f9536b69f21..aa249f63d9e5c44 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -299,8 +299,10 @@ dropRedundantMaskingOfLeftShiftInput(BinaryOperator *OuterShift,
 
     // And compute the mask as usual: (-1 l>> (NumHighBitsToClear))
     auto *ExtendedAllOnes = ConstantExpr::getAllOnesValue(ExtendedTy);
-    NewMask =
-        ConstantExpr::getLShr(ExtendedAllOnes, ExtendedNumHighBitsToClear);
+    NewMask = ConstantFoldBinaryOpOperands(Instruction::LShr, ExtendedAllOnes,
+                                           ExtendedNumHighBitsToClear, Q.DL);
+    if (!NewMask)
+      return nullptr;
   } else
     return nullptr; // Don't know anything about this pattern.