[llvm] [InstCombine] Always fold alignment assumptions into operand bundles (PR #177597)
via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 23 06:49:40 PST 2026
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: Nikolas Klauser (philnik777)
<details>
<summary>Changes</summary>
---
Full diff: https://github.com/llvm/llvm-project/pull/177597.diff
4 Files Affected:
- (modified) llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp (+1-2)
- (modified) llvm/test/Transforms/InstCombine/assume-loop-align.ll (+2-8)
- (modified) llvm/test/Transforms/InstCombine/assume.ll (+16-48)
- (modified) llvm/test/Transforms/InstCombine/assume_inevitable.ll (+1-4)
``````````diff
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 00b45545178ae..6b18e279e9596 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -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)),
diff --git a/llvm/test/Transforms/InstCombine/assume-loop-align.ll b/llvm/test/Transforms/InstCombine/assume-loop-align.ll
index 24fd343d1448e..7669d5bae5b08 100644
--- a/llvm/test/Transforms/InstCombine/assume-loop-align.ll
+++ b/llvm/test/Transforms/InstCombine/assume-loop-align.ll
@@ -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]] ]
diff --git a/llvm/test/Transforms/InstCombine/assume.ll b/llvm/test/Transforms/InstCombine/assume.ll
index cc87d6542fa12..a44c87149a98d 100644
--- a/llvm/test/Transforms/InstCombine/assume.ll
+++ b/llvm/test/Transforms/InstCombine/assume.ll
@@ -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
@@ -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
@@ -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
@@ -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
diff --git a/llvm/test/Transforms/InstCombine/assume_inevitable.ll b/llvm/test/Transforms/InstCombine/assume_inevitable.ll
index 5f27ff1e609ba..f899be41e0584 100644
--- a/llvm/test/Transforms/InstCombine/assume_inevitable.ll
+++ b/llvm/test/Transforms/InstCombine/assume_inevitable.ll
@@ -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:
``````````
</details>
https://github.com/llvm/llvm-project/pull/177597
More information about the llvm-commits
mailing list