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[InstCombine] Always fold alignment assumptions into operand bundles #177597

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Merged
philnik777 merged 1 commit into from
Jan 23, 2026
Merged

[InstCombine] Always fold alignment assumptions into operand bundles #177597

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3 changes: 1 addition & 2 deletions llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3671,8 +3671,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
// into
// call void @llvm.assume(i1 true) [ "align"(i32* [[A]], i64 Constant + 1)]
uint64_t AlignMask = 1;
if (EnableKnowledgeRetention &&
(match(IIOperand, m_Not(m_Trunc(m_Value(A)))) ||
if ((match(IIOperand, m_Not(m_Trunc(m_Value(A)))) ||
match(IIOperand,
m_SpecificICmp(ICmpInst::ICMP_EQ,
m_And(m_Value(A), m_ConstantInt(AlignMask)),
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10 changes: 2 additions & 8 deletions llvm/test/Transforms/InstCombine/assume-loop-align.ll
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Expand Up @@ -10,14 +10,8 @@ target triple = "x86_64-unknown-linux-gnu"
define void @foo(ptr %a, ptr %b) #0 {
; CHECK-LABEL: @foo(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[PTRINT:%.*]] = ptrtoint ptr [[A:%.*]] to i64
; CHECK-NEXT: [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 63
; CHECK-NEXT: [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
; CHECK-NEXT: tail call void @llvm.assume(i1 [[MASKCOND]])
; CHECK-NEXT: [[PTRINT1:%.*]] = ptrtoint ptr [[B:%.*]] to i64
; CHECK-NEXT: [[MASKEDPTR2:%.*]] = and i64 [[PTRINT1]], 63
; CHECK-NEXT: [[MASKCOND3:%.*]] = icmp eq i64 [[MASKEDPTR2]], 0
; CHECK-NEXT: tail call void @llvm.assume(i1 [[MASKCOND3]])
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A:%.*]], i64 64) ]
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[B:%.*]], i64 64) ]
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INDVARS_IV_NEXT:%.*]], [[FOR_BODY]] ]
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64 changes: 16 additions & 48 deletions llvm/test/Transforms/InstCombine/assume.ll
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Expand Up @@ -11,18 +11,10 @@ declare void @llvm.assume(i1) #1
; Check that the assume has not been removed:

define i32 @align_to_bundle(ptr %a) #0 {
; DEFAULT-LABEL: @align_to_bundle(
; DEFAULT-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; DEFAULT-NEXT: [[PTRINT:%.*]] = ptrtoint ptr [[A]] to i64
; DEFAULT-NEXT: [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
; DEFAULT-NEXT: [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
; DEFAULT-NEXT: tail call void @llvm.assume(i1 [[MASKCOND]])
; DEFAULT-NEXT: ret i32 [[T0]]
;
; BUNDLES-LABEL: @align_to_bundle(
; BUNDLES-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; BUNDLES-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 32) ]
; BUNDLES-NEXT: ret i32 [[T0]]
; CHECK-LABEL: @align_to_bundle(
; CHECK-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 32) ]
; CHECK-NEXT: ret i32 [[T0]]
;
%t0 = load i32, ptr %a, align 4
%ptrint = ptrtoint ptr %a to i64
Expand All @@ -33,18 +25,10 @@ define i32 @align_to_bundle(ptr %a) #0 {
}

define i32 @align_to_bundle_ptrtoaddr(ptr %a) #0 {
; DEFAULT-LABEL: @align_to_bundle_ptrtoaddr(
; DEFAULT-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; DEFAULT-NEXT: [[PTRINT:%.*]] = ptrtoaddr ptr [[A]] to i64
; DEFAULT-NEXT: [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
; DEFAULT-NEXT: [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
; DEFAULT-NEXT: tail call void @llvm.assume(i1 [[MASKCOND]])
; DEFAULT-NEXT: ret i32 [[T0]]
;
; BUNDLES-LABEL: @align_to_bundle_ptrtoaddr(
; BUNDLES-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; BUNDLES-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 32) ]
; BUNDLES-NEXT: ret i32 [[T0]]
; CHECK-LABEL: @align_to_bundle_ptrtoaddr(
; CHECK-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 32) ]
; CHECK-NEXT: ret i32 [[T0]]
;
%t0 = load i32, ptr %a, align 4
%ptrint = ptrtoaddr ptr %a to i64
Expand All @@ -55,18 +39,10 @@ define i32 @align_to_bundle_ptrtoaddr(ptr %a) #0 {
}

define i32 @align_assume_trunc_cond(ptr %a) #0 {
; DEFAULT-LABEL: @align_assume_trunc_cond(
; DEFAULT-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; DEFAULT-NEXT: [[PTRINT:%.*]] = ptrtoint ptr [[A]] to i64
; DEFAULT-NEXT: [[TRUNC:%.*]] = trunc i64 [[PTRINT]] to i1
; DEFAULT-NEXT: [[MASKCOND:%.*]] = xor i1 [[TRUNC]], true
; DEFAULT-NEXT: tail call void @llvm.assume(i1 [[MASKCOND]])
; DEFAULT-NEXT: ret i32 [[T0]]
;
; BUNDLES-LABEL: @align_assume_trunc_cond(
; BUNDLES-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; BUNDLES-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 2) ]
; BUNDLES-NEXT: ret i32 [[T0]]
; CHECK-LABEL: @align_assume_trunc_cond(
; CHECK-NEXT: [[T0:%.*]] = load i32, ptr [[A:%.*]], align 4
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 2) ]
; CHECK-NEXT: ret i32 [[T0]]
;
%t0 = load i32, ptr %a, align 4
%ptrint = ptrtoint ptr %a to i64
Expand All @@ -79,18 +55,10 @@ define i32 @align_assume_trunc_cond(ptr %a) #0 {
; Same check as in @foo1, but make sure it works if the assume is first too.

define i32 @foo2(ptr %a) #0 {
; DEFAULT-LABEL: @foo2(
; DEFAULT-NEXT: [[PTRINT:%.*]] = ptrtoint ptr [[A:%.*]] to i64
; DEFAULT-NEXT: [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
; DEFAULT-NEXT: [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
; DEFAULT-NEXT: tail call void @llvm.assume(i1 [[MASKCOND]])
; DEFAULT-NEXT: [[T0:%.*]] = load i32, ptr [[A]], align 4
; DEFAULT-NEXT: ret i32 [[T0]]
;
; BUNDLES-LABEL: @foo2(
; BUNDLES-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A:%.*]], i64 32) ]
; BUNDLES-NEXT: [[T0:%.*]] = load i32, ptr [[A]], align 4
; BUNDLES-NEXT: ret i32 [[T0]]
; CHECK-LABEL: @foo2(
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A:%.*]], i64 32) ]
; CHECK-NEXT: [[T0:%.*]] = load i32, ptr [[A]], align 4
; CHECK-NEXT: ret i32 [[T0]]
;
%ptrint = ptrtoint ptr %a to i64
%maskedptr = and i64 %ptrint, 31
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5 changes: 1 addition & 4 deletions llvm/test/Transforms/InstCombine/assume_inevitable.ll
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Expand Up @@ -16,10 +16,7 @@ define i32 @assume_inevitable(ptr %a, ptr %b, ptr %c) {
; CHECK-NEXT: [[M_A:%.*]] = call ptr @llvm.ptr.annotation.p0.p0(ptr nonnull [[M]], ptr nonnull @.str, ptr nonnull @.str1, i32 2, ptr null)
; CHECK-NEXT: [[OBJSZ:%.*]] = call i64 @llvm.objectsize.i64.p0(ptr [[C:%.*]], i1 false, i1 false, i1 false)
; CHECK-NEXT: store i64 [[OBJSZ]], ptr [[M_A]], align 4
; CHECK-NEXT: [[PTRINT:%.*]] = ptrtoint ptr [[A]] to i64
; CHECK-NEXT: [[MASKEDPTR:%.*]] = and i64 [[PTRINT]], 31
; CHECK-NEXT: [[MASKCOND:%.*]] = icmp eq i64 [[MASKEDPTR]], 0
; CHECK-NEXT: tail call void @llvm.assume(i1 [[MASKCOND]])
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 32) ]
; CHECK-NEXT: ret i32 [[TMP0]]
;
entry:
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