[llvm] b6cda33 - [Loads] Also consider getPointerAlignment when checking assumptions. (#120916)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 9 10:19:43 PST 2025
Author: Florian Hahn
Date: 2025-01-09T18:19:39Z
New Revision: b6cda338ab7bd18265a3e3fd494856620aec5210
URL: https://github.com/llvm/llvm-project/commit/b6cda338ab7bd18265a3e3fd494856620aec5210
DIFF: https://github.com/llvm/llvm-project/commit/b6cda338ab7bd18265a3e3fd494856620aec5210.diff
LOG: [Loads] Also consider getPointerAlignment when checking assumptions. (#120916)
Also use getPointerAlignment when trying to use alignment and
dereferenceable assumptions. This catches cases where dereferencable is
known via the assumption but alignment is known via getPointerAlignment
(e.g. via argument attribute or align of 1)
PR: https://github.com/llvm/llvm-project/pull/120916
Added:
Modified:
llvm/lib/Analysis/Loads.cpp
llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-constant-size.ll
Removed:
################################################################################
diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index bc03e4052a705b..7bbd469bd035d3 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -170,9 +170,10 @@ static bool isDereferenceableAndAlignedPointer(
if (CtxI) {
/// Look through assumes to see if both dereferencability and alignment can
- /// be provent by an assume
+ /// be proven by an assume if needed.
RetainedKnowledge AlignRK;
RetainedKnowledge DerefRK;
+ bool IsAligned = V->getPointerAlignment(DL) >= Alignment;
if (getKnowledgeForValue(
V, {Attribute::Dereferenceable, Attribute::Alignment}, AC,
[&](RetainedKnowledge RK, Instruction *Assume, auto) {
@@ -182,7 +183,8 @@ static bool isDereferenceableAndAlignedPointer(
AlignRK = std::max(AlignRK, RK);
if (RK.AttrKind == Attribute::Dereferenceable)
DerefRK = std::max(DerefRK, RK);
- if (AlignRK && DerefRK && AlignRK.ArgValue >= Alignment.value() &&
+ IsAligned |= AlignRK && AlignRK.ArgValue >= Alignment.value();
+ if (IsAligned && DerefRK &&
DerefRK.ArgValue >= Size.getZExtValue())
return true; // We have found what we needed so we stop looking
return false; // Other assumes may have better information. so
diff --git a/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-constant-size.ll b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-constant-size.ll
index 1333451a0077e3..815e6bce52c0a1 100644
--- a/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-constant-size.ll
+++ b/llvm/test/Transforms/LoopVectorize/dereferenceable-info-from-assumption-constant-size.ll
@@ -104,8 +104,8 @@ exit:
ret void
}
-define void @deref_assumption_in_header_constant_trip_count_loop_invariant_ptr(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
-; CHECK-LABEL: define void @deref_assumption_in_header_constant_trip_count_loop_invariant_ptr(
+define void @align_deref_assumption_in_header_constant_trip_count_loop_invariant_ptr(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
+; CHECK-LABEL: define void @align_deref_assumption_in_header_constant_trip_count_loop_invariant_ptr(
; CHECK-SAME: ptr noalias [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*]]:
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr [[A]], i64 4), "dereferenceable"(ptr [[A]], i64 4) ]
@@ -899,32 +899,15 @@ define void @deref_assumption_in_preheader_constant_trip_count_align_1(ptr noali
; CHECK: [[VECTOR_PH]]:
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
-; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP0:%.*]] = add i64 [[INDEX]], 0
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i32 0
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP2]], align 4
; CHECK-NEXT: [[TMP3:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
-; CHECK-NEXT: [[TMP4:%.*]] = xor <2 x i1> [[TMP3]], splat (i1 true)
-; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP4]], i32 0
-; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
-; CHECK: [[PRED_LOAD_IF]]:
; CHECK-NEXT: [[TMP6:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP0]]
-; CHECK-NEXT: [[TMP7:%.*]] = load i32, ptr [[TMP6]], align 1
-; CHECK-NEXT: [[TMP8:%.*]] = insertelement <2 x i32> poison, i32 [[TMP7]], i32 0
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
-; CHECK: [[PRED_LOAD_CONTINUE]]:
-; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i32> [ poison, %[[VECTOR_BODY]] ], [ [[TMP8]], %[[PRED_LOAD_IF]] ]
-; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP4]], i32 1
-; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_IF1]]:
-; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[INDEX]], 1
-; CHECK-NEXT: [[TMP12:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP11]]
-; CHECK-NEXT: [[TMP13:%.*]] = load i32, ptr [[TMP12]], align 1
-; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i32> [[TMP9]], i32 [[TMP13]], i32 1
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_CONTINUE2]]:
-; CHECK-NEXT: [[TMP15:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[TMP5:%.*]] = getelementptr i32, ptr [[TMP6]], i32 0
+; CHECK-NEXT: [[TMP15:%.*]] = load <2 x i32>, ptr [[TMP5]], align 1
; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP3]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[TMP15]]
; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP17:%.*]] = getelementptr inbounds i32, ptr [[TMP16]], i32 0
@@ -1168,32 +1151,15 @@ define void @deref_assumption_in_preheader_constant_trip_count_align_4_known_via
; CHECK: [[VECTOR_PH]]:
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
-; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_LOAD_CONTINUE2:.*]] ]
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP0:%.*]] = add i64 [[INDEX]], 0
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i32 0
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <2 x i32>, ptr [[TMP2]], align 4
; CHECK-NEXT: [[TMP3:%.*]] = icmp sge <2 x i32> [[WIDE_LOAD]], zeroinitializer
-; CHECK-NEXT: [[TMP4:%.*]] = xor <2 x i1> [[TMP3]], splat (i1 true)
-; CHECK-NEXT: [[TMP5:%.*]] = extractelement <2 x i1> [[TMP4]], i32 0
-; CHECK-NEXT: br i1 [[TMP5]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
-; CHECK: [[PRED_LOAD_IF]]:
; CHECK-NEXT: [[TMP6:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP0]]
-; CHECK-NEXT: [[TMP7:%.*]] = load i32, ptr [[TMP6]], align 4
-; CHECK-NEXT: [[TMP8:%.*]] = insertelement <2 x i32> poison, i32 [[TMP7]], i32 0
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE]]
-; CHECK: [[PRED_LOAD_CONTINUE]]:
-; CHECK-NEXT: [[TMP9:%.*]] = phi <2 x i32> [ poison, %[[VECTOR_BODY]] ], [ [[TMP8]], %[[PRED_LOAD_IF]] ]
-; CHECK-NEXT: [[TMP10:%.*]] = extractelement <2 x i1> [[TMP4]], i32 1
-; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_IF1]]:
-; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[INDEX]], 1
-; CHECK-NEXT: [[TMP12:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP11]]
-; CHECK-NEXT: [[TMP13:%.*]] = load i32, ptr [[TMP12]], align 4
-; CHECK-NEXT: [[TMP14:%.*]] = insertelement <2 x i32> [[TMP9]], i32 [[TMP13]], i32 1
-; CHECK-NEXT: br label %[[PRED_LOAD_CONTINUE2]]
-; CHECK: [[PRED_LOAD_CONTINUE2]]:
-; CHECK-NEXT: [[TMP15:%.*]] = phi <2 x i32> [ [[TMP9]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP14]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT: [[TMP5:%.*]] = getelementptr i32, ptr [[TMP6]], i32 0
+; CHECK-NEXT: [[TMP15:%.*]] = load <2 x i32>, ptr [[TMP5]], align 4
; CHECK-NEXT: [[PREDPHI:%.*]] = select <2 x i1> [[TMP3]], <2 x i32> [[WIDE_LOAD]], <2 x i32> [[TMP15]]
; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[C]], i64 [[TMP0]]
; CHECK-NEXT: [[TMP17:%.*]] = getelementptr inbounds i32, ptr [[TMP16]], i32 0
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