[llvm] 0abc8b0 - [LV] Add early-exit test where the inner loop IV depends on outer loop.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 26 02:53:37 PDT 2025
Author: Florian Hahn
Date: 2025-08-26T10:52:53+01:00
New Revision: 0abc8b07e5e643a1e96aabd3d21a1ecc9bf0ade0
URL: https://github.com/llvm/llvm-project/commit/0abc8b07e5e643a1e96aabd3d21a1ecc9bf0ade0
DIFF: https://github.com/llvm/llvm-project/commit/0abc8b07e5e643a1e96aabd3d21a1ecc9bf0ade0.diff
LOG: [LV] Add early-exit test where the inner loop IV depends on outer loop.
Added:
Modified:
llvm/test/Transforms/LoopVectorize/single_early_exit.ll
Removed:
################################################################################
diff --git a/llvm/test/Transforms/LoopVectorize/single_early_exit.ll b/llvm/test/Transforms/LoopVectorize/single_early_exit.ll
index 5885e67dadaee..adc37a579363f 100644
--- a/llvm/test/Transforms/LoopVectorize/single_early_exit.ll
+++ b/llvm/test/Transforms/LoopVectorize/single_early_exit.ll
@@ -329,6 +329,103 @@ early.exit:
for.end:
ret i32 0
}
+
+define void @inner_loop_trip_count_depends_on_outer_iv(ptr align 8 dereferenceable(1792) %this, ptr %dst) {
+; CHECK-LABEL: define void @inner_loop_trip_count_depends_on_outer_iv(
+; CHECK-SAME: ptr align 8 dereferenceable(1792) [[THIS:%.*]], ptr [[DST:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[GEP_SRC:%.*]] = getelementptr i8, ptr [[THIS]], i64 1000
+; CHECK-NEXT: br label [[OUTER_HEADER:%.*]]
+; CHECK: outer.header:
+; CHECK-NEXT: [[OUTER_IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[OUTER_IV_NEXT:%.*]], [[OUTER_LATCH:%.*]] ]
+; CHECK-NEXT: [[C_1:%.*]] = icmp eq i64 [[OUTER_IV]], 0
+; CHECK-NEXT: br i1 [[C_1]], label [[THEN:%.*]], label [[INNER_HEADER_PREHEADER:%.*]]
+; CHECK: inner.header.preheader:
+; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[OUTER_IV]], 4
+; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK: vector.ph:
+; CHECK-NEXT: [[N_MOD_VF:%.*]] = urem i64 [[OUTER_IV]], 4
+; CHECK-NEXT: [[N_VEC:%.*]] = sub i64 [[OUTER_IV]], [[N_MOD_VF]]
+; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
+; CHECK: vector.body:
+; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT: [[TMP0:%.*]] = getelementptr ptr, ptr [[GEP_SRC]], i64 [[INDEX]]
+; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x ptr>, ptr [[TMP0]], align 8
+; CHECK-NEXT: [[TMP1:%.*]] = icmp eq <4 x ptr> [[WIDE_LOAD]], zeroinitializer
+; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
+; CHECK-NEXT: [[TMP2:%.*]] = freeze <4 x i1> [[TMP1]]
+; CHECK-NEXT: [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT: [[TMP5:%.*]] = or i1 [[TMP3]], [[TMP4]]
+; CHECK-NEXT: br i1 [[TMP5]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
+; CHECK: middle.split:
+; CHECK-NEXT: br i1 [[TMP3]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; CHECK: middle.block:
+; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[OUTER_IV]], [[N_VEC]]
+; CHECK-NEXT: br i1 [[CMP_N]], label [[OUTER_LATCH_LOOPEXIT:%.*]], label [[SCALAR_PH]]
+; CHECK: vector.early.exit:
+; CHECK-NEXT: br label [[THEN_LOOPEXIT:%.*]]
+; CHECK: scalar.ph:
+; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[INNER_HEADER_PREHEADER]] ]
+; CHECK-NEXT: br label [[INNER_HEADER:%.*]]
+; CHECK: inner.header:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[INNER_LATCH:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; CHECK-NEXT: [[GEP_IV:%.*]] = getelementptr ptr, ptr [[GEP_SRC]], i64 [[IV]]
+; CHECK-NEXT: [[L:%.*]] = load ptr, ptr [[GEP_IV]], align 8
+; CHECK-NEXT: [[C_2:%.*]] = icmp eq ptr [[L]], null
+; CHECK-NEXT: br i1 [[C_2]], label [[THEN_LOOPEXIT]], label [[INNER_LATCH]]
+; CHECK: inner.latch:
+; CHECK-NEXT: [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[IV_NEXT]], [[OUTER_IV]]
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[OUTER_LATCH_LOOPEXIT]], label [[INNER_HEADER]], !llvm.loop [[LOOP11:![0-9]+]]
+; CHECK: then.loopexit:
+; CHECK-NEXT: br label [[THEN]]
+; CHECK: then:
+; CHECK-NEXT: store i32 0, ptr [[DST]], align 4
+; CHECK-NEXT: br label [[OUTER_LATCH]]
+; CHECK: outer.latch.loopexit:
+; CHECK-NEXT: br label [[OUTER_LATCH]]
+; CHECK: outer.latch:
+; CHECK-NEXT: [[OUTER_IV_NEXT]] = add i64 [[OUTER_IV]], 1
+; CHECK-NEXT: [[OUTER_EC:%.*]] = icmp eq i64 [[OUTER_IV_NEXT]], 100
+; CHECK-NEXT: br i1 [[OUTER_EC]], label [[EXIT:%.*]], label [[OUTER_HEADER]]
+; CHECK: exit:
+; CHECK-NEXT: ret void
+;
+entry:
+ %gep.src = getelementptr i8, ptr %this, i64 1000
+ br label %outer.header
+
+outer.header:
+ %outer.iv = phi i64 [ 0, %entry ], [ %outer.iv.next, %outer.latch ]
+ %c.1 = icmp eq i64 %outer.iv, 0
+ br i1 %c.1, label %then, label %inner.header
+
+inner.header:
+ %iv = phi i64 [ %iv.next, %inner.latch ], [ 0, %outer.header ]
+ %gep.iv = getelementptr ptr, ptr %gep.src, i64 %iv
+ %l = load ptr, ptr %gep.iv, align 8
+ %c.2 = icmp eq ptr %l, null
+ br i1 %c.2, label %then, label %inner.latch
+
+inner.latch:
+ %iv.next = add i64 %iv, 1
+ %exitcond.not = icmp eq i64 %iv.next, %outer.iv
+ br i1 %exitcond.not, label %outer.latch, label %inner.header
+
+then:
+ store i32 0, ptr %dst, align 4
+ br label %outer.latch
+
+outer.latch:
+ %outer.iv.next = add i64 %outer.iv, 1
+ %outer.ec = icmp eq i64 %outer.iv.next, 100
+ br i1 %outer.ec, label %exit, label %outer.header
+
+exit:
+ ret void
+}
+
;.
; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
@@ -340,4 +437,6 @@ for.end:
; CHECK: [[LOOP7]] = distinct !{[[LOOP7]], [[META1]]}
; CHECK: [[LOOP8]] = distinct !{[[LOOP8]], [[META1]], [[META2]]}
; CHECK: [[LOOP9]] = distinct !{[[LOOP9]], [[META2]], [[META1]]}
+; CHECK: [[LOOP10]] = distinct !{[[LOOP10]], [[META1]], [[META2]]}
+; CHECK: [[LOOP11]] = distinct !{[[LOOP11]], [[META2]], [[META1]]}
;.
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