[llvm] f628a54 - [ConstantFold] Fold inttoptr, ptrtoaddr to bitcast (#161087)

[via llvm-commits]

Author: Hongyu Chen
Date: 2025-09-29T18:38:50+08:00
New Revision: f628a5467addf2f8a597141ab01f7e7453e6d9a7

URL: https://github.com/llvm/llvm-project/commit/f628a5467addf2f8a597141ab01f7e7453e6d9a7
DIFF: https://github.com/llvm/llvm-project/commit/f628a5467addf2f8a597141ab01f7e7453e6d9a7.diff

LOG: [ConstantFold] Fold inttoptr, ptrtoaddr to bitcast (#161087)

Fixes #157334.

Added: 
    llvm/test/Transforms/InstCombine/ptrtoaddr.ll

Modified: 
    llvm/lib/IR/Instructions.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index daebf447a2107..dd83168ab3c6e 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -2847,6 +2847,7 @@ unsigned CastInst::isEliminableCastPair(
   // FPTRUNC       >       FloatPt      n/a        FloatPt      n/a
   // FPEXT         <       FloatPt      n/a        FloatPt      n/a
   // PTRTOINT     n/a      Pointer      n/a        Integral   Unsigned
+  // PTRTOADDR    n/a      Pointer      n/a        Integral   Unsigned
   // INTTOPTR     n/a      Integral   Unsigned     Pointer      n/a
   // BITCAST       =       FirstClass   n/a       FirstClass    n/a
   // ADDRSPCST    n/a      Pointer      n/a        Pointer      n/a
@@ -2878,7 +2879,7 @@ unsigned CastInst::isEliminableCastPair(
     { 99,99,99, 2, 2,99,99, 8, 2,99,99,99, 4, 0}, // FPExt          |
     {  1, 0, 0,99,99, 0, 0,99,99,99,99, 7, 3, 0}, // PtrToInt       |
     {  1, 0, 0,99,99, 0, 0,99,99,99,99, 0, 3, 0}, // PtrToAddr      |
-    { 99,99,99,99,99,99,99,99,99,11,99,99,15, 0}, // IntToPtr       |
+    { 99,99,99,99,99,99,99,99,99,11,11,99,15, 0}, // IntToPtr       |
     {  5, 5, 5, 0, 0, 5, 5, 0, 0,16,16, 5, 1,14}, // BitCast        |
     {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,13,12}, // AddrSpaceCast -+
   };
@@ -2972,7 +2973,8 @@ unsigned CastInst::isEliminableCastPair(
       // zext, sext -> zext, because sext can't sign extend after zext
       return Instruction::ZExt;
     case 11: {
-      // inttoptr, ptrtoint -> bitcast if SrcSize<=PtrSize and SrcSize==DstSize
+      // inttoptr, ptrtoint/ptrtoaddr -> bitcast if SrcSize<=PtrSize and
+      // SrcSize==DstSize
       if (!MidIntPtrTy)
         return 0;
       unsigned PtrSize = MidIntPtrTy->getScalarSizeInBits();

diff  --git a/llvm/test/Transforms/InstCombine/ptrtoaddr.ll b/llvm/test/Transforms/InstCombine/ptrtoaddr.ll
new file mode 100644
index 0000000000000..61b13312521d2
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/ptrtoaddr.ll
@@ -0,0 +1,65 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+target datalayout = "p1:64:64:64:32"
+
+define i32 @ptrtoaddr_inttoptr_arg(i32 %a) {
+; CHECK-LABEL: define i32 @ptrtoaddr_inttoptr_arg(
+; CHECK-SAME: i32 [[A:%.*]]) {
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i32 [[A]] to i64
+; CHECK-NEXT:    [[TOPTR:%.*]] = inttoptr i64 [[TMP1]] to ptr addrspace(1)
+; CHECK-NEXT:    [[TOADDR:%.*]] = ptrtoaddr ptr addrspace(1) [[TOPTR]] to i32
+; CHECK-NEXT:    ret i32 [[TOADDR]]
+;
+  %toptr = inttoptr i32 %a to ptr addrspace(1)
+  %toaddr = ptrtoaddr ptr addrspace(1) %toptr to i32
+  ret i32 %toaddr
+}
+
+define i32 @ptrtoaddr_inttoptr() {
+; CHECK-LABEL: define i32 @ptrtoaddr_inttoptr() {
+; CHECK-NEXT:    ret i32 -1
+;
+  ret i32 ptrtoaddr (ptr addrspace(1) inttoptr (i32 -1 to ptr addrspace(1)) to i32)
+}
+
+define i32 @ptrtoaddr_inttoptr_
diff _size1() {
+; CHECK-LABEL: define i32 @ptrtoaddr_inttoptr_
diff _size1() {
+; CHECK-NEXT:    ret i32 ptrtoaddr (ptr addrspace(1) inttoptr (i64 -1 to ptr addrspace(1)) to i32)
+;
+  ret i32 ptrtoaddr (ptr addrspace(1) inttoptr (i64 -1 to ptr addrspace(1)) to i32)
+}
+
+define i32 @ptrtoaddr_inttoptr_
diff _size2() {
+; CHECK-LABEL: define i32 @ptrtoaddr_inttoptr_
diff _size2() {
+; CHECK-NEXT:    ret i32 ptrtoaddr (ptr addrspace(1) inttoptr (i16 -1 to ptr addrspace(1)) to i32)
+;
+  ret i32 ptrtoaddr (ptr addrspace(1) inttoptr (i16 -1 to ptr addrspace(1)) to i32)
+}
+
+define i64 @ptrtoaddr_inttoptr_noas1() {
+; CHECK-LABEL: define i64 @ptrtoaddr_inttoptr_noas1() {
+; CHECK-NEXT:    ret i64 1
+;
+  ret i64 ptrtoaddr (ptr getelementptr (i8, ptr null, i64 1) to i64)
+}
+
+define i64 @ptr2addr2_inttoptr_noas2() {
+; CHECK-LABEL: define i64 @ptr2addr2_inttoptr_noas2() {
+; CHECK-NEXT:    ret i64 123
+;
+  ret i64 ptrtoaddr (ptr inttoptr (i64 123 to ptr) to i64)
+}
+
+define i64 @ptrtoaddr_inttoptr_noas_
diff _size1() {
+; CHECK-LABEL: define i64 @ptrtoaddr_inttoptr_noas_
diff _size1() {
+; CHECK-NEXT:    ret i64 ptrtoaddr (ptr inttoptr (i32 -1 to ptr) to i64)
+;
+  ret i64 ptrtoaddr (ptr inttoptr (i32 -1 to ptr) to i64)
+}
+
+define i64 @ptrtoaddr_inttoptr_noas_
diff _size2() {
+; CHECK-LABEL: define i64 @ptrtoaddr_inttoptr_noas_
diff _size2() {
+; CHECK-NEXT:    ret i64 ptrtoaddr (ptr inttoptr (i128 -1 to ptr) to i64)
+;
+  ret i64 ptrtoaddr (ptr inttoptr (i128 -1 to ptr) to i64)
+}