[llvm] 0afbf17 - [LAA,LV] Add tests with early-exit loops and deref assumptions.

Florian Hahn via llvm-commits llvm-commits at lists.llvm.org
Thu Jul 3 11:41:41 PDT 2025


Author: Florian Hahn
Date: 2025-07-03T19:41:13+01:00
New Revision: 0afbf1721346faca3dbcd659acf2c558c26146fb

URL: https://github.com/llvm/llvm-project/commit/0afbf1721346faca3dbcd659acf2c558c26146fb
DIFF: https://github.com/llvm/llvm-project/commit/0afbf1721346faca3dbcd659acf2c558c26146fb.diff

LOG: [LAA,LV] Add tests with early-exit loops and deref assumptions.

Adds additional test coverage for early-exit loops with deref
assumptions, as suggested in
https://github.com/llvm/llvm-project/pull/128436.

Added: 
    llvm/test/Transforms/LoopVectorize/single-early-exit-deref-assumptions.ll

Modified: 
    llvm/test/Analysis/LoopAccessAnalysis/early-exit-runtime-checks.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Analysis/LoopAccessAnalysis/early-exit-runtime-checks.ll b/llvm/test/Analysis/LoopAccessAnalysis/early-exit-runtime-checks.ll
index d4cd61bfde2f4..1dc8d4a7e73f8 100644
--- a/llvm/test/Analysis/LoopAccessAnalysis/early-exit-runtime-checks.ll
+++ b/llvm/test/Analysis/LoopAccessAnalysis/early-exit-runtime-checks.ll
@@ -504,3 +504,123 @@ e.0:
 e.1:
   ret i32 1
 }
+
+define void @all_exits_dominate_latch_countable_exits_at_most_500_iterations_known_deref_via_assumption(ptr %A, ptr %B) {
+; CHECK-LABEL: 'all_exits_dominate_latch_countable_exits_at_most_500_iterations_known_deref_via_assumption'
+; CHECK-NEXT:    loop.header:
+; CHECK-NEXT:      Memory dependences are safe with run-time checks
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:      Run-time memory checks:
+; CHECK-NEXT:      Check 0:
+; CHECK-NEXT:        Comparing group GRP0:
+; CHECK-NEXT:          %gep.B = getelementptr inbounds i32, ptr %B, i64 %iv
+; CHECK-NEXT:        Against group GRP1:
+; CHECK-NEXT:          %gep.A = getelementptr inbounds i32, ptr %A, i64 %iv
+; CHECK-NEXT:      Grouped accesses:
+; CHECK-NEXT:        Group GRP0:
+; CHECK-NEXT:          (Low: %B High: inttoptr (i64 -1 to ptr))
+; CHECK-NEXT:            Member: {%B,+,4}<nuw><%loop.header>
+; CHECK-NEXT:        Group GRP1:
+; CHECK-NEXT:          (Low: %A High: inttoptr (i64 -1 to ptr))
+; CHECK-NEXT:            Member: {%A,+,4}<nuw><%loop.header>
+; CHECK-EMPTY:
+; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:      SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Expressions re-written:
+;
+entry:
+  call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %A, i64 2000) ]
+  call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %B, i64 2000) ]
+  br label %loop.header
+
+loop.header:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %latch ]
+  %gep.A = getelementptr inbounds i32, ptr %A, i64 %iv
+  %gep.B = getelementptr inbounds i32, ptr %B, i64 %iv
+  %l = load i32, ptr %gep.A, align 4
+  store i32 0, ptr %gep.B, align 4
+  %cntable.c.1 = icmp ult i64 %iv, 1000
+  %iv.next = add nuw nsw i64 %iv, 1
+  br i1 %cntable.c.1, label %b2, label %e.1
+
+b2:
+  %uncntable.c.0 = icmp eq i32 %l, 0
+  br i1 %uncntable.c.0, label %e.2, label %b3
+
+b3:
+  %cntable.c.2 = icmp eq i64 %iv.next, 500
+  br i1 %cntable.c.2, label %cleanup4, label %latch
+
+latch:
+  br label %loop.header
+
+cleanup4:
+  ret void
+
+e.1:
+  ret void
+
+e.2:
+  ret void
+}
+
+define void @all_exits_dominate_latch_countable_exits_at_most_500_iterations_deref_via_assumption_too_small(ptr %A, ptr %B) {
+; CHECK-LABEL: 'all_exits_dominate_latch_countable_exits_at_most_500_iterations_deref_via_assumption_too_small'
+; CHECK-NEXT:    loop.header:
+; CHECK-NEXT:      Memory dependences are safe with run-time checks
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:      Run-time memory checks:
+; CHECK-NEXT:      Check 0:
+; CHECK-NEXT:        Comparing group GRP0:
+; CHECK-NEXT:          %gep.B = getelementptr inbounds i32, ptr %B, i64 %iv
+; CHECK-NEXT:        Against group GRP1:
+; CHECK-NEXT:          %gep.A = getelementptr inbounds i32, ptr %A, i64 %iv
+; CHECK-NEXT:      Grouped accesses:
+; CHECK-NEXT:        Group GRP0:
+; CHECK-NEXT:          (Low: %B High: inttoptr (i64 -1 to ptr))
+; CHECK-NEXT:            Member: {%B,+,4}<nuw><%loop.header>
+; CHECK-NEXT:        Group GRP1:
+; CHECK-NEXT:          (Low: %A High: inttoptr (i64 -1 to ptr))
+; CHECK-NEXT:            Member: {%A,+,4}<nuw><%loop.header>
+; CHECK-EMPTY:
+; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:      SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT:      Expressions re-written:
+;
+entry:
+  call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %A, i64 1999) ]
+  call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %B, i64 1999) ]
+  br label %loop.header
+
+loop.header:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %latch ]
+  %gep.A = getelementptr inbounds i32, ptr %A, i64 %iv
+  %gep.B = getelementptr inbounds i32, ptr %B, i64 %iv
+  %l = load i32, ptr %gep.A, align 4
+  store i32 0, ptr %gep.B, align 4
+  %cntable.c.1 = icmp ult i64 %iv, 1000
+  %iv.next = add nuw nsw i64 %iv, 1
+  br i1 %cntable.c.1, label %b2, label %e.1
+
+b2:
+  %uncntable.c.0 = icmp eq i32 %l, 0
+  br i1 %uncntable.c.0, label %e.2, label %b3
+
+b3:
+  %cntable.c.2 = icmp eq i64 %iv.next, 500
+  br i1 %cntable.c.2, label %cleanup4, label %latch
+
+latch:
+  br label %loop.header
+
+cleanup4:
+  ret void
+
+e.1:
+  ret void
+
+e.2:
+  ret void
+}

diff  --git a/llvm/test/Transforms/LoopVectorize/single-early-exit-deref-assumptions.ll b/llvm/test/Transforms/LoopVectorize/single-early-exit-deref-assumptions.ll
new file mode 100644
index 0000000000000..0fe893abec86c
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/single-early-exit-deref-assumptions.ll
@@ -0,0 +1,96 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 4
+; RUN: opt -S < %s -p loop-vectorize -enable-early-exit-vectorization -force-vector-width=4 | FileCheck %s
+
+define i64 @early_exit_alignment_and_deref_known_via_assumption_with_constant_size(ptr noalias %p1, ptr noalias %p2) nofree nosync {
+; CHECK-LABEL: define i64 @early_exit_alignment_and_deref_known_via_assumption_with_constant_size(
+; CHECK-SAME: ptr noalias [[P1:%.*]], ptr noalias [[P2:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[P1]], i64 4), "dereferenceable"(ptr [[P1]], i64 1024) ]
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[P2]], i64 4), "dereferenceable"(ptr [[P2]], i64 1024) ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ [[INDEX_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[INDEX]]
+; CHECK-NEXT:    [[LD1:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[INDEX]]
+; CHECK-NEXT:    [[LD2:%.*]] = load i8, ptr [[ARRAYIDX1]], align 1
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; CHECK-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END:%.*]]
+; CHECK:       loop.inc:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[INDEX_NEXT]], 1024
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[LOOP]], label [[LOOP_END]]
+; CHECK:       loop.end:
+; CHECK-NEXT:    [[RETVAL:%.*]] = phi i64 [ [[INDEX]], [[LOOP]] ], [ -1, [[LOOP_INC]] ]
+; CHECK-NEXT:    ret i64 [[RETVAL]]
+;
+entry:
+  call void @llvm.assume(i1 true) [ "align"(ptr %p1, i64 4), "dereferenceable"(ptr %p1, i64 1024) ]
+  call void @llvm.assume(i1 true) [ "align"(ptr %p2, i64 4), "dereferenceable"(ptr %p2, i64 1024) ]
+  br label %loop
+
+loop:
+  %index = phi i64 [ %index.next, %loop.inc ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
+  %ld1 = load i8, ptr %arrayidx, align 1
+  %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
+  %ld2 = load i8, ptr %arrayidx1, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %index.next = add i64 %index, 1
+  %exitcond = icmp ne i64 %index.next, 1024
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.end:
+  %retval = phi i64 [ %index, %loop ], [ -1, %loop.inc ]
+  ret i64 %retval
+}
+
+define i64 @early_exit_alignment_and_deref_via_assumption_with_constant_size_too_small(ptr noalias %p1, ptr noalias %p2) nofree nosync {
+; CHECK-LABEL: define i64 @early_exit_alignment_and_deref_via_assumption_with_constant_size_too_small(
+; CHECK-SAME: ptr noalias [[P1:%.*]], ptr noalias [[P2:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[P1]], i64 4), "dereferenceable"(ptr [[P1]], i64 1024) ]
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(ptr [[P2]], i64 4), "dereferenceable"(ptr [[P2]], i64 1024) ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ [[INDEX_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[INDEX]]
+; CHECK-NEXT:    [[LD1:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[INDEX]]
+; CHECK-NEXT:    [[LD2:%.*]] = load i8, ptr [[ARRAYIDX1]], align 1
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; CHECK-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END:%.*]]
+; CHECK:       loop.inc:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[INDEX_NEXT]], 1025
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[LOOP]], label [[LOOP_END]]
+; CHECK:       loop.end:
+; CHECK-NEXT:    [[RETVAL:%.*]] = phi i64 [ [[INDEX]], [[LOOP]] ], [ -1, [[LOOP_INC]] ]
+; CHECK-NEXT:    ret i64 [[RETVAL]]
+;
+entry:
+  call void @llvm.assume(i1 true) [ "align"(ptr %p1, i64 4), "dereferenceable"(ptr %p1, i64 1024) ]
+  call void @llvm.assume(i1 true) [ "align"(ptr %p2, i64 4), "dereferenceable"(ptr %p2, i64 1024) ]
+  br label %loop
+
+loop:
+  %index = phi i64 [ %index.next, %loop.inc ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i8, ptr %p1, i64 %index
+  %ld1 = load i8, ptr %arrayidx, align 1
+  %arrayidx1 = getelementptr inbounds i8, ptr %p2, i64 %index
+  %ld2 = load i8, ptr %arrayidx1, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %index.next = add i64 %index, 1
+  %exitcond = icmp ne i64 %index.next, 1025
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.end:
+  %retval = phi i64 [ %index, %loop ], [ -1, %loop.inc ]
+  ret i64 %retval
+}


        


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