[LICM] Prevent LICM of ptrtoint and inttoptr when using non-integral pointers

llvm/lib/Transforms/Scalar/LICM.cpp

@@ -65,11 +65,12 @@
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Dominators.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/IR/PredIteratorCache.h"
 #include "llvm/InitializePasses.h"
@@ -1328,6 +1329,20 @@ bool llvm::canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
           }
       }
     return true;
+  } else if (auto *PTII = dyn_cast<PtrToIntInst>(&I)) {
+    const DataLayout &DL = I.getModule()->getDataLayout();
+    // Non-integral pointers may not have a stable bit representation, therefore
+    // casting them to an integer is not loop invariant.
+    if (DL.isNonIntegralPointerType(PTII->getPointerOperand()->getType())) {
+      return false;
+    }
+  } else if (auto *ITPI = dyn_cast<IntToPtrInst>(&I)) {
+    const DataLayout &DL = I.getModule()->getDataLayout();
+    // Non-integral pointers may not have a stable bit representation, therefore
+    // casting an integer to a non-integral pointer type is not loop invariant.
+    if (DL.isNonIntegralPointerType(ITPI->getType())) {
+      return false;
+    }
   }
 
   assert(!I.mayReadOrWriteMemory() && "unhandled aliasing");

llvm/test/Transforms/LICM/non-integral-pointers.ll

@@ -0,0 +1,96 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=licm -S < %s | FileCheck %s
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-ni:1"
+
+declare void @use_i64(i64 %0)
+declare void @use_p1(ptr addrspace(1) %0)
+declare i1 @cond()
+
+define void @dont_hoist_ptrtoint(ptr addrspace(1) %p) {
+; CHECK-LABEL: define void @dont_hoist_ptrtoint(
+; CHECK-SAME: ptr addrspace(1) [[P:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[P_INT:%.*]] = ptrtoint ptr addrspace(1) [[P]] to i64
+; CHECK-NEXT:    call void @use_i64(i64 [[P_INT]])
+; CHECK-NEXT:    br label %[[LOOP]]
+;
+entry:
+  br label %loop
+
+loop:
+  %p.int = ptrtoint ptr addrspace(1) %p to i64
+  call void @use_i64(i64 %p.int)
+  br label %loop
+}
+
+define void @dont_hoist_inttoptr(i64 %p.int) {
+; CHECK-LABEL: define void @dont_hoist_inttoptr(
+; CHECK-SAME: i64 [[P_INT:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[P:%.*]] = inttoptr i64 [[P_INT]] to ptr addrspace(1)
+; CHECK-NEXT:    call void @use_p1(ptr addrspace(1) [[P]])
+; CHECK-NEXT:    br label %[[LOOP]]
+;
+entry:
+  br label %loop
+
+loop:
+  %p = inttoptr i64 %p.int to ptr addrspace(1)
+  call void @use_p1(ptr addrspace(1) %p)
+  br label %loop
+}
+
+define i64 @dont_sink_ptrtoint(ptr addrspace(1) %p) {
+; CHECK-LABEL: define i64 @dont_sink_ptrtoint(
+; CHECK-SAME: ptr addrspace(1) [[P:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[P_INT_LE:%.*]] = ptrtoint ptr addrspace(1) [[P]] to i64
+; CHECK-NEXT:    [[C:%.*]] = call i1 @cond()
+; CHECK-NEXT:    br i1 [[C]], label %[[LOOP]], label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    [[P_INT_LCSSA:%.*]] = phi i64 [ [[P_INT_LE]], %[[LOOP]] ]
+; CHECK-NEXT:    ret i64 [[P_INT_LCSSA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %p.int = ptrtoint ptr addrspace(1) %p to i64
+  %c = call i1 @cond()
+  br i1 %c, label %loop, label %exit
+
+exit:
+  ret i64 %p.int
+}
+
+define ptr addrspace(1) @dont_sink_inttoptr(i64 %p.int) {
+; CHECK-LABEL: define ptr addrspace(1) @dont_sink_inttoptr(
+; CHECK-SAME: i64 [[P_INT:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br label %[[LOOP:.*]]
+; CHECK:       [[LOOP]]:
+; CHECK-NEXT:    [[P_LE:%.*]] = inttoptr i64 [[P_INT]] to ptr addrspace(1)
+; CHECK-NEXT:    [[C:%.*]] = call i1 @cond()
+; CHECK-NEXT:    br i1 [[C]], label %[[LOOP]], label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    [[P_LCSSA:%.*]] = phi ptr addrspace(1) [ [[P_LE]], %[[LOOP]] ]
+; CHECK-NEXT:    ret ptr addrspace(1) [[P_LCSSA]]
+;
+entry:
+  br label %loop
+
+loop:
+  %p = inttoptr i64 %p.int to ptr addrspace(1)
+  %c = call i1 @cond()
+  br i1 %c, label %loop, label %exit
+
+exit:
+  ret ptr addrspace(1) %p
+}