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[InstComb] Fold inttoptr (add (ptrtoint %B), %O) -> GEP for ICMP users. #153421

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Merged
fhahn merged 4 commits into from
Aug 21, 2025
Merged

[InstComb] Fold inttoptr (add (ptrtoint %B), %O) -> GEP for ICMP users. #153421

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43e4b11
[InstComb] Fold inttoptr (add (ptrtoint %B), %O) -> GEP for ICMP users.
fhahn Aug 13, 2025
5ed4d71
!fixup use m_PtrToIntSameSize
fhahn Aug 13, 2025
c012a9c
!fixup use m_c_Add
fhahn Aug 21, 2025
9d16660
!fixup check add has one use.
fhahn Aug 21, 2025
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13 changes: 13 additions & 0 deletions llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2072,6 +2072,19 @@ Instruction *InstCombinerImpl::visitIntToPtr(IntToPtrInst &CI) {
return new IntToPtrInst(P, CI.getType());
}

// Replace (inttoptr (add (ptrtoint %Base), %Offset)) with
// (getelementptr i8, %Base, %Offset) if all users are ICmps.
Value *Base;
Value *Offset;
if (match(CI.getOperand(0),
m_OneUse(m_c_Add(m_PtrToIntSameSize(DL, m_Value(Base)),
m_Value(Offset)))) &&
CI.getType()->getPointerAddressSpace() ==
Base->getType()->getPointerAddressSpace() &&
all_of(CI.users(), IsaPred<ICmpInst>)) {
return GetElementPtrInst::Create(Builder.getInt8Ty(), Base, Offset);
}

if (Instruction *I = commonCastTransforms(CI))
return I;

Expand Down
56 changes: 31 additions & 25 deletions llvm/test/Transforms/InstCombine/fold-bin-operand.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -32,10 +32,8 @@ define i32 @g(i32 %x) {

define i1 @inttoptr_add_ptrtoint_used_by_single_icmp(ptr %src, ptr %p2) {
; CHECK-LABEL: @inttoptr_add_ptrtoint_used_by_single_icmp(
; CHECK-NEXT: [[I:%.*]] = ptrtoint ptr [[SRC:%.*]] to i64
; CHECK-NEXT: [[A:%.*]] = add i64 [[I]], 10
; CHECK-NEXT: [[P:%.*]] = inttoptr i64 [[A]] to ptr
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2:%.*]], [[P]]
; CHECK-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[SRC:%.*]], i64 10
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2]], [[P:%.*]]
; CHECK-NEXT: ret i1 [[C]]
;
%i = ptrtoint ptr %src to i64
Expand All @@ -47,10 +45,8 @@ define i1 @inttoptr_add_ptrtoint_used_by_single_icmp(ptr %src, ptr %p2) {

define i1 @inttoptr_add_ptrtoint_used_by_single_icmp_operands_swapped(ptr %src, ptr %p2) {
; CHECK-LABEL: @inttoptr_add_ptrtoint_used_by_single_icmp_operands_swapped(
; CHECK-NEXT: [[I:%.*]] = ptrtoint ptr [[SRC:%.*]] to i64
; CHECK-NEXT: [[A:%.*]] = add i64 [[I]], 10
; CHECK-NEXT: [[P:%.*]] = inttoptr i64 [[A]] to ptr
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2:%.*]], [[P]]
; CHECK-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[SRC:%.*]], i64 10
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2]], [[P:%.*]]
; CHECK-NEXT: ret i1 [[C]]
;
%i = ptrtoint ptr %src to i64
Expand All @@ -62,10 +58,8 @@ define i1 @inttoptr_add_ptrtoint_used_by_single_icmp_operands_swapped(ptr %src,

define i1 @inttoptr_add_ptrtoint_used_by_single_icmp_constant_offset(ptr %src, i64 %off, ptr %p2) {
; CHECK-LABEL: @inttoptr_add_ptrtoint_used_by_single_icmp_constant_offset(
; CHECK-NEXT: [[I:%.*]] = ptrtoint ptr [[SRC:%.*]] to i64
; CHECK-NEXT: [[A:%.*]] = add i64 [[OFF:%.*]], [[I]]
; CHECK-NEXT: [[P:%.*]] = inttoptr i64 [[A]] to ptr
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2:%.*]], [[P]]
; CHECK-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[SRC:%.*]], i64 [[OFF:%.*]]
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2]], [[P:%.*]]
; CHECK-NEXT: ret i1 [[C]]
;
%i = ptrtoint ptr %src to i64
Expand All @@ -77,10 +71,8 @@ define i1 @inttoptr_add_ptrtoint_used_by_single_icmp_constant_offset(ptr %src, i

define i1 @inttoptr_add_ptrtoint_used_by_single_icmp_constant_offset_operands_swapped(ptr %src, i64 %off, ptr %p2) {
; CHECK-LABEL: @inttoptr_add_ptrtoint_used_by_single_icmp_constant_offset_operands_swapped(
; CHECK-NEXT: [[I:%.*]] = ptrtoint ptr [[SRC:%.*]] to i64
; CHECK-NEXT: [[A:%.*]] = add i64 [[OFF:%.*]], [[I]]
; CHECK-NEXT: [[P:%.*]] = inttoptr i64 [[A]] to ptr
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2:%.*]], [[P]]
; CHECK-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[SRC:%.*]], i64 [[OFF:%.*]]
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2]], [[P:%.*]]
; CHECK-NEXT: ret i1 [[C]]
;
%i = ptrtoint ptr %src to i64
Expand Down Expand Up @@ -137,6 +129,23 @@ define i1 @inttoptr_add_ptrtoint_used_by_single_icmp_int_type_does_not_match_ptr
ret i1 %c
}

define i1 @inttoptr_add_multiple_users_ptrtoint_used_by_single_icmp(ptr %src, ptr %p2) {
; CHECK-LABEL: @inttoptr_add_multiple_users_ptrtoint_used_by_single_icmp(
; CHECK-NEXT: [[I:%.*]] = ptrtoint ptr [[SRC:%.*]] to i64
; CHECK-NEXT: [[A:%.*]] = add i64 [[I]], 10
; CHECK-NEXT: [[P:%.*]] = inttoptr i64 [[A]] to ptr
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2:%.*]], [[P]]
; CHECK-NEXT: call void @bar(i64 [[A]])
; CHECK-NEXT: ret i1 [[C]]
;
%i = ptrtoint ptr %src to i64
%a = add i64 %i, 10
%p = inttoptr i64 %a to ptr
%c = icmp eq ptr %p, %p2
call void @bar(i64 %a)
ret i1 %c
}

define i1 @multiple_inttoptr_add_ptrtoint_used_by_single_icmp(ptr %src) {
; CHECK-LABEL: @multiple_inttoptr_add_ptrtoint_used_by_single_icmp(
; CHECK-NEXT: ret i1 false
Expand Down Expand Up @@ -181,10 +190,8 @@ define i1 @inttoptr_add_ptrtoint_used_by_single_icmp_in_different_bb(i1 %bc, ptr
; CHECK-LABEL: @inttoptr_add_ptrtoint_used_by_single_icmp_in_different_bb(
; CHECK-NEXT: br i1 [[BC:%.*]], label [[THEN:%.*]], label [[ELSE:%.*]]
; CHECK: then:
; CHECK-NEXT: [[I:%.*]] = ptrtoint ptr [[SRC:%.*]] to i64
; CHECK-NEXT: [[A:%.*]] = add i64 [[I]], 10
; CHECK-NEXT: [[P:%.*]] = inttoptr i64 [[A]] to ptr
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2:%.*]], [[P]]
; CHECK-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[SRC:%.*]], i64 10
; CHECK-NEXT: [[C:%.*]] = icmp eq ptr [[P2]], [[P:%.*]]
; CHECK-NEXT: ret i1 [[C]]
; CHECK: else:
; CHECK-NEXT: ret i1 false
Expand All @@ -204,11 +211,9 @@ else:

define i1 @inttoptr_add_ptrtoint_used_by_multiple_icmps(ptr %src, ptr %p2, ptr %p3) {
; CHECK-LABEL: @inttoptr_add_ptrtoint_used_by_multiple_icmps(
; CHECK-NEXT: [[I:%.*]] = ptrtoint ptr [[SRC:%.*]] to i64
; CHECK-NEXT: [[A:%.*]] = add i64 [[I]], 10
; CHECK-NEXT: [[P:%.*]] = inttoptr i64 [[A]] to ptr
; CHECK-NEXT: [[C_1:%.*]] = icmp eq ptr [[P2:%.*]], [[P]]
; CHECK-NEXT: [[C_2:%.*]] = icmp eq ptr [[P3:%.*]], [[P]]
; CHECK-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[SRC:%.*]], i64 10
; CHECK-NEXT: [[C_1:%.*]] = icmp eq ptr [[P2]], [[P:%.*]]
; CHECK-NEXT: [[C_2:%.*]] = icmp eq ptr [[P2]], [[P3:%.*]]
; CHECK-NEXT: [[XOR:%.*]] = xor i1 [[C_1]], [[C_2]]
; CHECK-NEXT: ret i1 [[XOR]]
;
Expand All @@ -222,6 +227,7 @@ define i1 @inttoptr_add_ptrtoint_used_by_multiple_icmps(ptr %src, ptr %p2, ptr %
}

declare void @foo(ptr)
declare void @bar(i64)

define i1 @inttoptr_add_ptrtoint_used_by_multiple_icmps_and_other_user(ptr %src, ptr %p2, ptr %p3) {
; CHECK-LABEL: @inttoptr_add_ptrtoint_used_by_multiple_icmps_and_other_user(
Expand Down