[PATCH] D105088: [InstCombine] Fold IntToPtr/PtrToInt to bitcast

[Krishna Kariya via Phabricator via llvm-commits]

Krishnakariya updated this revision to Diff 356797.
Krishnakariya added a comment.

Added the check and test case for the same.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D105088/new/

https://reviews.llvm.org/D105088

Files:
  llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
  llvm/test/Transforms/InstCombine/ptr-int-ptr-icmp.ll


Index: llvm/test/Transforms/InstCombine/ptr-int-ptr-icmp.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/InstCombine/ptr-int-ptr-icmp.ll
@@ -0,0 +1,62 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -instcombine -S  < %s | FileCheck %s
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; icmp (inttoptr (ptrtoint p1)), p2 --> icmp p1, p2.
+
+define i1 @func(i8* %X, i8* %Y) {
+; CHECK-LABEL: @func(
+; CHECK-NEXT:    [[I:%.*]] = ptrtoint i8* [[X:%.*]] to i64
+; CHECK-NEXT:    [[P:%.*]] = inttoptr i64 [[I]] to i8*
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8* [[P]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %i = ptrtoint i8* %X to i64
+  %p = inttoptr i64 %i to i8*
+  %cmp = icmp eq i8* %p, %Y
+  ret i1 %cmp
+}
+
+define i1 @func2(i16* %X, i8* %Y) {
+; CHECK-LABEL: @func2(
+; CHECK-NEXT:    [[I:%.*]] = ptrtoint i16* [[X:%.*]] to i64
+; CHECK-NEXT:    [[P:%.*]] = inttoptr i64 [[I]] to i8*
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8* [[P]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %i = ptrtoint i16* %X to i64
+  %p = inttoptr i64 %i to i8*
+  %cmp = icmp eq i8* %p, %Y
+  ret i1 %cmp
+}
+
+define i1 @func3(i16* %X, i8* %Y) {
+; CHECK-LABEL: @func3(
+; CHECK-NEXT:    [[I:%.*]] = ptrtoint i16* [[X:%.*]] to i64
+; CHECK-NEXT:    [[P:%.*]] = inttoptr i64 [[I]] to i8*
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8* [[P]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %i = ptrtoint i16* %X to i64
+  %p = inttoptr i64 %i to i8*
+  %cmp = icmp eq i8* %Y, %p
+  ret i1 %cmp
+}
+
+; Negative test - Wrong Integer type.
+
+define i1 @func4(i16* %X, i8* %Y) {
+; CHECK-LABEL: @func4(
+; CHECK-NEXT:    [[TMP1:%.*]] = ptrtoint i16* [[X:%.*]] to i64
+; CHECK-NEXT:    [[TMP2:%.*]] = and i64 [[TMP1]], 4294967295
+; CHECK-NEXT:    [[P:%.*]] = inttoptr i64 [[TMP2]] to i8*
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8* [[P]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %i = ptrtoint i16* %X to i32
+  %p = inttoptr i32 %i to i8*
+  %cmp = icmp eq i8* %Y, %p
+  ret i1 %cmp
+}
Index: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4539,6 +4539,21 @@
   auto *CastOp0 = dyn_cast<CastInst>(ICmp.getOperand(0));
   if (!CastOp0)
     return nullptr;
+
+  // icmp (inttoptr (ptrtoint p1)), p2 --> icmp p1, p2.
+  if (CastOp0->getOpcode() == Instruction::IntToPtr &&
+      (DL.getPointerTypeSizeInBits(CastOp0->getDestTy()) ==
+       DL.getTypeSizeInBits(CastOp0->getSrcTy()))) {
+    auto *I = dyn_cast<PtrToIntInst>(CastOp0->getOperand(0));
+    if (I) {
+      Value *P = I->getOperand(0);
+      Type *Op0Ty = CastOp0->getDestTy();
+      Value *NewOp0 = nullptr;
+      NewOp0 = Builder.CreateBitCast(P, Op0Ty);
+      return new ICmpInst(ICmp.getPredicate(), NewOp0, ICmp.getOperand(1));
+    }
+  }
+
   if (!isa<Constant>(ICmp.getOperand(1)) && !isa<CastInst>(ICmp.getOperand(1)))
     return nullptr;
 


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