[llvm] 8249d67 - [InstCombine] Avoid uses of ConstantExpr::getOr()

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-07-24T16:50:45+02:00
New Revision: 8249d6724ccd8876b421dd96151dab98fa45210c

URL: https://github.com/llvm/llvm-project/commit/8249d6724ccd8876b421dd96151dab98fa45210c
DIFF: https://github.com/llvm/llvm-project/commit/8249d6724ccd8876b421dd96151dab98fa45210c.diff

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

Replace these with IRBuilder uses, as we don't (from a type
perspective) care about Constant results.

Switch the predicate to m_ImmConstant() instead of isa<Constant>
to guarantee that these do get folded away and our assumptions
about simplifications hold true.

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 0268db22b5d516..5c84f666616d28 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -735,13 +735,12 @@ Instruction *InstCombinerImpl::visitTrunc(TruncInst &Trunc) {
       Value *And = Builder.CreateAnd(X, MaskC);
       return new ICmpInst(ICmpInst::ICMP_NE, And, Zero);
     }
-    if (match(Src, m_OneUse(m_c_Or(m_LShr(m_Value(X), m_Constant(C)),
+    if (match(Src, m_OneUse(m_c_Or(m_LShr(m_Value(X), m_ImmConstant(C)),
                                    m_Deferred(X))))) {
       // trunc (or (lshr X, C), X) to i1 --> icmp ne (and X, C'), 0
       Constant *One = ConstantInt::get(SrcTy, APInt(SrcWidth, 1));
       Constant *MaskC = ConstantExpr::getShl(One, C);
-      MaskC = ConstantExpr::getOr(MaskC, One);
-      Value *And = Builder.CreateAnd(X, MaskC);
+      Value *And = Builder.CreateAnd(X, Builder.CreateOr(MaskC, One));
       return new ICmpInst(ICmpInst::ICMP_NE, And, Zero);
     }
   }

diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 9b3a661520dc51..656f04370e17da 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1834,17 +1834,12 @@ Instruction *InstCombinerImpl::foldICmpAndConstConst(ICmpInst &Cmp,
         ++UsesRemoved;
 
       // Compute A & ((1 << B) | 1)
-      Value *NewOr = nullptr;
-      if (auto *C = dyn_cast<Constant>(B)) {
-        if (UsesRemoved >= 1)
-          NewOr = ConstantExpr::getOr(ConstantExpr::getNUWShl(One, C), One);
-      } else {
-        if (UsesRemoved >= 3)
-          NewOr = Builder.CreateOr(Builder.CreateShl(One, B, LShr->getName(),
-                                                     /*HasNUW=*/true),
-                                   One, Or->getName());
-      }
-      if (NewOr) {
+      unsigned RequireUsesRemoved = match(B, m_ImmConstant()) ? 1 : 3;
+      if (UsesRemoved >= RequireUsesRemoved) {
+        Value *NewOr =
+            Builder.CreateOr(Builder.CreateShl(One, B, LShr->getName(),
+                                               /*HasNUW=*/true),
+                             One, Or->getName());
         Value *NewAnd = Builder.CreateAnd(A, NewOr, And->getName());
         return replaceOperand(Cmp, 0, NewAnd);
       }