[llvm] b054363 - [LV] Add tests showing incorrect vector interleaving with early exits.

Florian Hahn via llvm-commits llvm-commits at lists.llvm.org
Mon Jun 23 08:24:48 PDT 2025


Author: Florian Hahn
Date: 2025-06-23T16:24:13+01:00
New Revision: b054363645122e131071673bb67657a85f04a146

URL: https://github.com/llvm/llvm-project/commit/b054363645122e131071673bb67657a85f04a146
DIFF: https://github.com/llvm/llvm-project/commit/b054363645122e131071673bb67657a85f04a146.diff

LOG: [LV] Add tests showing incorrect vector interleaving with early exits.

When interleaving is forced for early-exit loops, we currently create
incorrect code.

Test coverage for scalable vectors is added as AArch64 specific test.

Added: 
    llvm/test/Transforms/LoopVectorize/AArch64/single-early-exit-interleave.ll
    llvm/test/Transforms/LoopVectorize/single-early-exit-interleave.ll

Modified: 
    

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/LoopVectorize/AArch64/single-early-exit-interleave.ll b/llvm/test/Transforms/LoopVectorize/AArch64/single-early-exit-interleave.ll
new file mode 100644
index 0000000000000..9dfe70ddf1b05
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/single-early-exit-interleave.ll
@@ -0,0 +1,99 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 4
+; RUN: opt -p loop-vectorize -enable-early-exit-vectorization -force-vector-interleave=4 -S %s | FileCheck %s
+
+target triple = "aarch64-unknown-linux-gnu"
+
+declare void @init_mem(ptr, i64);
+
+define i64 @same_exit_block_pre_inc_use1() #0 {
+; CHECK-LABEL: define i64 @same_exit_block_pre_inc_use1(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 4
+; CHECK-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 4
+; CHECK-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; CHECK-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; CHECK-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP1:%.*]] = mul nuw i64 [[TMP0]], 64
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 510, [[TMP1]]
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 64
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 510, [[TMP3]]
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 510, [[N_MOD_VF]]
+; CHECK-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP5:%.*]] = mul nuw i64 [[TMP4]], 64
+; CHECK-NEXT:    [[INDEX_NEXT:%.*]] = add i64 3, [[N_VEC]]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX1:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT3:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i64 3, [[INDEX1]]
+; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[OFFSET_IDX]]
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr inbounds i8, ptr [[TMP7]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 16 x i8>, ptr [[TMP8]], align 1
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[OFFSET_IDX]]
+; CHECK-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i8, ptr [[TMP9]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD2:%.*]] = load <vscale x 16 x i8>, ptr [[TMP10]], align 1
+; CHECK-NEXT:    [[TMP11:%.*]] = icmp ne <vscale x 16 x i8> [[WIDE_LOAD]], [[WIDE_LOAD2]]
+; CHECK-NEXT:    [[INDEX_NEXT3]] = add nuw i64 [[INDEX1]], [[TMP5]]
+; CHECK-NEXT:    [[TMP12:%.*]] = call i1 @llvm.vector.reduce.or.nxv16i1(<vscale x 16 x i1> [[TMP11]])
+; CHECK-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[INDEX_NEXT3]], [[N_VEC]]
+; CHECK-NEXT:    [[TMP14:%.*]] = or i1 [[TMP12]], [[TMP13]]
+; CHECK-NEXT:    br i1 [[TMP14]], label [[MIDDLE_SPLIT:%.*]], label [[LOOP]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       middle.split:
+; CHECK-NEXT:    br i1 [[TMP12]], label [[VECTOR_EARLY_EXIT:%.*]], label [[LOOP_INC:%.*]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 510, [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; CHECK:       vector.early.exit:
+; CHECK-NEXT:    [[TMP15:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.nxv16i1(<vscale x 16 x i1> [[TMP11]], i1 true)
+; CHECK-NEXT:    [[TMP16:%.*]] = add i64 [[INDEX1]], [[TMP15]]
+; CHECK-NEXT:    [[TMP17:%.*]] = add i64 3, [[TMP16]]
+; CHECK-NEXT:    br label [[LOOP_END]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ [[INDEX_NEXT]], [[LOOP_INC]] ], [ 3, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br label [[LOOP1:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[INDEX2:%.*]] = phi i64 [ [[INDEX_NEXT1:%.*]], [[LOOP_INC1:%.*]] ], [ [[INDEX]], [[SCALAR_PH]] ]
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[INDEX2]]
+; CHECK-NEXT:    [[LD1:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
+; CHECK-NEXT:    [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[INDEX2]]
+; CHECK-NEXT:    [[LD2:%.*]] = load i8, ptr [[ARRAYIDX1]], align 1
+; CHECK-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; CHECK-NEXT:    br i1 [[CMP3]], label [[LOOP_INC1]], label [[LOOP_END]]
+; CHECK:       loop.inc:
+; CHECK-NEXT:    [[INDEX_NEXT1]] = add i64 [[INDEX2]], 1
+; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[INDEX_NEXT1]], 513
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[LOOP1]], label [[LOOP_END]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK:       loop.end:
+; CHECK-NEXT:    [[RETVAL:%.*]] = phi i64 [ [[INDEX2]], [[LOOP1]] ], [ 67, [[LOOP_INC1]] ], [ 67, [[LOOP_INC]] ], [ [[TMP17]], [[VECTOR_EARLY_EXIT]] ]
+; CHECK-NEXT:    ret i64 [[RETVAL]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %index = phi i64 [ %index.next, %loop.inc ], [ 3, %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, 513
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.end:
+  %retval = phi i64 [ %index, %loop ], [ 67, %loop.inc ]
+  ret i64 %retval
+}
+
+attributes #0 = { "target-features"="+sve" vscale_range(1,16) }

diff  --git a/llvm/test/Transforms/LoopVectorize/single-early-exit-interleave.ll b/llvm/test/Transforms/LoopVectorize/single-early-exit-interleave.ll
new file mode 100644
index 0000000000000..1f8cfa1bfd11c
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/single-early-exit-interleave.ll
@@ -0,0 +1,724 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 4
+; RUN: opt -p loop-vectorize -enable-early-exit-vectorization -force-vector-width=4 -force-vector-interleave=4 -S %s | FileCheck --check-prefix=VF4IC4 %s
+
+declare void @init_mem(ptr, i64);
+
+; FIXME: Computes incorrect final IV when early exit is taken.
+define i64 @multi_exiting_to_
diff erent_exits_live_in_exit_values() {
+; VF4IC4-LABEL: define i64 @multi_exiting_to_
diff erent_exits_live_in_exit_values() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[SRC:%.*]] = alloca [128 x i32], align 4
+; VF4IC4-NEXT:    call void @init_mem(ptr [[SRC]])
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i64 [[INDEX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP1]], align 4
+; VF4IC4-NEXT:    [[TMP2:%.*]] = icmp eq <4 x i32> [[WIDE_LOAD]], splat (i32 10)
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; VF4IC4-NEXT:    [[TMP4:%.*]] = icmp eq i64 [[INDEX_NEXT]], 128
+; VF4IC4-NEXT:    [[TMP5:%.*]] = or i1 [[TMP3]], [[TMP4]]
+; VF4IC4-NEXT:    br i1 [[TMP5]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP3]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 true, label [[E2:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    br label [[E1:%.*]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 128, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP_HEADER:%.*]]
+; VF4IC4:       loop.header:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[INC:%.*]], [[LOOP_LATCH:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_SRC:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i64 [[IV]]
+; VF4IC4-NEXT:    [[L:%.*]] = load i32, ptr [[GEP_SRC]], align 4
+; VF4IC4-NEXT:    [[C_1:%.*]] = icmp eq i32 [[L]], 10
+; VF4IC4-NEXT:    br i1 [[C_1]], label [[E1]], label [[LOOP_LATCH]]
+; VF4IC4:       loop.latch:
+; VF4IC4-NEXT:    [[INC]] = add nuw i64 [[IV]], 1
+; VF4IC4-NEXT:    [[C_2:%.*]] = icmp eq i64 [[INC]], 128
+; VF4IC4-NEXT:    br i1 [[C_2]], label [[E2]], label [[LOOP_HEADER]], !llvm.loop [[LOOP3:![0-9]+]]
+; VF4IC4:       e1:
+; VF4IC4-NEXT:    [[P1:%.*]] = phi i64 [ 0, [[LOOP_HEADER]] ], [ 0, [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i64 [[P1]]
+; VF4IC4:       e2:
+; VF4IC4-NEXT:    [[P2:%.*]] = phi i64 [ 1, [[LOOP_LATCH]] ], [ 1, [[MIDDLE_BLOCK]] ]
+; VF4IC4-NEXT:    ret i64 [[P2]]
+;
+entry:
+  %src = alloca [128 x i32]
+  call void @init_mem(ptr %src)
+  br label %loop.header
+
+loop.header:
+  %iv = phi i64 [ %inc, %loop.latch ], [ 0, %entry ]
+  %gep.src = getelementptr inbounds i32, ptr %src, i64 %iv
+  %l = load i32, ptr %gep.src
+  %c.1 = icmp eq i32 %l, 10
+  br i1 %c.1, label %e1, label %loop.latch
+
+loop.latch:
+  %inc = add nuw i64 %iv, 1
+  %c.2 = icmp eq i64 %inc, 128
+  br i1 %c.2, label %e2, label %loop.header
+
+e1:
+  %p1 = phi i64 [ 0, %loop.header ]
+  ret i64 %p1
+
+e2:
+  %p2 = phi i64 [ 1, %loop.latch ]
+  ret i64 %p2
+}
+
+; FIXME: Computes incorrect final IV when early exit is taken.
+define i64 @same_exit_block_pre_inc_use1() {
+; VF4IC4-LABEL: define i64 @same_exit_block_pre_inc_use1() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = add i64 3, [[INDEX]]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP1]], align 1
+; VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP3]], align 1
+; VF4IC4-NEXT:    [[TMP4:%.*]] = icmp ne <4 x i8> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 64
+; VF4IC4-NEXT:    [[TMP7:%.*]] = or i1 [[TMP5]], [[TMP6]]
+; VF4IC4-NEXT:    br i1 [[TMP7]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP5]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 true, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[TMP8:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP4]], i1 true)
+; VF4IC4-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], [[TMP8]]
+; VF4IC4-NEXT:    [[TMP10:%.*]] = add i64 3, [[TMP9]]
+; VF4IC4-NEXT:    br label [[LOOP_END]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 67, [[MIDDLE_BLOCK]] ], [ 3, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_P1:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[GEP_P1]], align 1
+; VF4IC4-NEXT:    [[GEP_P2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD2:%.*]] = load i8, ptr [[GEP_P2]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[IV_NEXT]], 67
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP]], label [[LOOP_END]], !llvm.loop [[LOOP5:![0-9]+]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL:%.*]] = phi i64 [ [[IV]], [[LOOP]] ], [ 67, [[LOOP_INC]] ], [ 67, [[MIDDLE_BLOCK]] ], [ [[TMP10]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i64 [[RETVAL]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop.inc ], [ 3, %entry ]
+  %gep.p1 = getelementptr inbounds i8, ptr %p1, i64 %iv
+  %ld1 = load i8, ptr %gep.p1, align 1
+  %gep.p2 = getelementptr inbounds i8, ptr %p2, i64 %iv
+  %ld2 = load i8, ptr %gep.p2, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %iv.next = add i64 %iv, 1
+  %exitcond = icmp ne i64 %iv.next, 67
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.end:
+  %retval = phi i64 [ %iv, %loop ], [ 67, %loop.inc ]
+  ret i64 %retval
+}
+
+; FIXME: Computes incorrect final IV when early exit is taken.
+define ptr @same_exit_block_pre_inc_use1_ivptr() {
+; VF4IC4-LABEL: define ptr @same_exit_block_pre_inc_use1_ivptr() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    [[PTREND:%.*]] = getelementptr i8, ptr [[P1]], i64 1024
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr i8, ptr [[P1]], i64 1024
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[NEXT_GEP:%.*]] = getelementptr i8, ptr [[P1]], i64 [[INDEX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr i8, ptr [[NEXT_GEP]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP1]], align 1
+; VF4IC4-NEXT:    [[TMP2:%.*]] = icmp ne <4 x i8> [[WIDE_LOAD]], splat (i8 72)
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP3:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP2]])
+; VF4IC4-NEXT:    [[TMP4:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1024
+; VF4IC4-NEXT:    [[TMP5:%.*]] = or i1 [[TMP3]], [[TMP4]]
+; VF4IC4-NEXT:    br i1 [[TMP5]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP3]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 true, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[TMP6:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP2]], i1 true)
+; VF4IC4-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], [[TMP6]]
+; VF4IC4-NEXT:    [[TMP8:%.*]] = getelementptr i8, ptr [[P1]], i64 [[TMP7]]
+; VF4IC4-NEXT:    br label [[LOOP_END]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi ptr [ [[TMP0]], [[MIDDLE_BLOCK]] ], [ [[P1]], [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[PTR:%.*]] = phi ptr [ [[PTR_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[PTR]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], 72
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[PTR_NEXT]] = getelementptr inbounds i8, ptr [[PTR]], i64 1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp ne ptr [[PTR_NEXT]], [[PTREND]]
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP]], label [[LOOP_END]], !llvm.loop [[LOOP7:![0-9]+]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL:%.*]] = phi ptr [ [[PTR]], [[LOOP]] ], [ [[PTREND]], [[LOOP_INC]] ], [ [[PTREND]], [[MIDDLE_BLOCK]] ], [ [[TMP8]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret ptr [[RETVAL]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  %ptrend = getelementptr i8, ptr %p1, i64 1024
+  br label %loop
+
+loop:
+  %ptr = phi ptr [ %ptr.next, %loop.inc ], [ %p1, %entry ]
+  %ld1 = load i8, ptr %ptr, align 1
+  %cmp3 = icmp eq i8 %ld1, 72
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %ptr.next = getelementptr inbounds i8, ptr %ptr, i64 1
+  %exitcond = icmp ne ptr %ptr.next, %ptrend
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.end:
+  %retval = phi ptr [ %ptr, %loop ], [ %ptrend, %loop.inc ]
+  ret ptr %retval
+}
+
+; FIXME: Computes incorrect final IV when early exit is taken.
+define i64 @same_exit_block_post_inc_use() {
+; VF4IC4-LABEL: define i64 @same_exit_block_post_inc_use() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = add i64 3, [[INDEX]]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP1]], align 1
+; VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP3]], align 1
+; VF4IC4-NEXT:    [[TMP4:%.*]] = icmp ne <4 x i8> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 64
+; VF4IC4-NEXT:    [[TMP7:%.*]] = or i1 [[TMP5]], [[TMP6]]
+; VF4IC4-NEXT:    br i1 [[TMP7]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP5]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 true, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[TMP8:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP4]], i1 true)
+; VF4IC4-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], [[TMP8]]
+; VF4IC4-NEXT:    [[TMP10:%.*]] = add i64 3, [[TMP9]]
+; VF4IC4-NEXT:    br label [[LOOP_END]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 67, [[MIDDLE_BLOCK]] ], [ 3, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_P1:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[GEP_P1]], align 1
+; VF4IC4-NEXT:    [[GEP_P2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD2:%.*]] = load i8, ptr [[GEP_P2]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[IV_NEXT]], 67
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP]], label [[LOOP_END]], !llvm.loop [[LOOP9:![0-9]+]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL:%.*]] = phi i64 [ [[IV]], [[LOOP]] ], [ [[IV_NEXT]], [[LOOP_INC]] ], [ 67, [[MIDDLE_BLOCK]] ], [ [[TMP10]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i64 [[RETVAL]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop.inc ], [ 3, %entry ]
+  %gep.p1 = getelementptr inbounds i8, ptr %p1, i64 %iv
+  %ld1 = load i8, ptr %gep.p1, align 1
+  %gep.p2 = getelementptr inbounds i8, ptr %p2, i64 %iv
+  %ld2 = load i8, ptr %gep.p2, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %iv.next = add i64 %iv, 1
+  %exitcond = icmp ne i64 %iv.next, 67
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.end:
+  %retval = phi i64 [ %iv, %loop ], [ %iv.next, %loop.inc ]
+  ret i64 %retval
+}
+
+; FIXME: Computes incorrect final IV when early exit is taken.
+define i64 @
diff _exit_block_pre_inc_use1() {
+; VF4IC4-LABEL: define i64 @
diff _exit_block_pre_inc_use1() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = add i64 3, [[INDEX]]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP1]], align 1
+; VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP3]], align 1
+; VF4IC4-NEXT:    [[TMP4:%.*]] = icmp ne <4 x i8> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 64
+; VF4IC4-NEXT:    [[TMP7:%.*]] = or i1 [[TMP5]], [[TMP6]]
+; VF4IC4-NEXT:    br i1 [[TMP7]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP5]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 true, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[TMP8:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP4]], i1 true)
+; VF4IC4-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], [[TMP8]]
+; VF4IC4-NEXT:    [[TMP10:%.*]] = add i64 3, [[TMP9]]
+; VF4IC4-NEXT:    br label [[LOOP_EARLY_EXIT:%.*]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 67, [[MIDDLE_BLOCK]] ], [ 3, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_P1:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[GEP_P1]], align 1
+; VF4IC4-NEXT:    [[GEP_P2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD2:%.*]] = load i8, ptr [[GEP_P2]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_EARLY_EXIT]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[IV_NEXT]], 67
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP]], label [[LOOP_END]], !llvm.loop [[LOOP11:![0-9]+]]
+; VF4IC4:       loop.early.exit:
+; VF4IC4-NEXT:    [[RETVAL1:%.*]] = phi i64 [ [[IV]], [[LOOP]] ], [ [[TMP10]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i64 [[RETVAL1]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL2:%.*]] = phi i64 [ 67, [[LOOP_INC]] ], [ 67, [[MIDDLE_BLOCK]] ]
+; VF4IC4-NEXT:    ret i64 [[RETVAL2]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop.inc ], [ 3, %entry ]
+  %gep.p1 = getelementptr inbounds i8, ptr %p1, i64 %iv
+  %ld1 = load i8, ptr %gep.p1, align 1
+  %gep.p2 = getelementptr inbounds i8, ptr %p2, i64 %iv
+  %ld2 = load i8, ptr %gep.p2, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.early.exit
+
+loop.inc:
+  %iv.next = add i64 %iv, 1
+  %exitcond = icmp ne i64 %iv.next, 67
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.early.exit:
+  %retval1 = phi i64 [ %iv, %loop ]
+  ret i64 %retval1
+
+loop.end:
+  %retval2 = phi i64 [ 67, %loop.inc ]
+  ret i64 %retval2
+}
+
+; FIXME: Computes incorrect final IV when early exit is taken.
+define i64 @
diff _exit_block_post_inc_use1() {
+; VF4IC4-LABEL: define i64 @
diff _exit_block_post_inc_use1() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = add i64 3, [[INDEX]]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP1]], align 1
+; VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP3]], align 1
+; VF4IC4-NEXT:    [[TMP4:%.*]] = icmp ne <4 x i8> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 64
+; VF4IC4-NEXT:    [[TMP7:%.*]] = or i1 [[TMP5]], [[TMP6]]
+; VF4IC4-NEXT:    br i1 [[TMP7]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP12:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP5]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 true, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[TMP8:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP4]], i1 true)
+; VF4IC4-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], [[TMP8]]
+; VF4IC4-NEXT:    [[TMP10:%.*]] = add i64 3, [[TMP9]]
+; VF4IC4-NEXT:    br label [[LOOP_EARLY_EXIT:%.*]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 67, [[MIDDLE_BLOCK]] ], [ 3, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_P1:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[GEP_P1]], align 1
+; VF4IC4-NEXT:    [[GEP_P2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD2:%.*]] = load i8, ptr [[GEP_P2]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_EARLY_EXIT]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp ne i64 [[IV_NEXT]], 67
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP]], label [[LOOP_END]], !llvm.loop [[LOOP13:![0-9]+]]
+; VF4IC4:       loop.early.exit:
+; VF4IC4-NEXT:    [[RETVAL1:%.*]] = phi i64 [ [[IV]], [[LOOP]] ], [ [[TMP10]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i64 [[RETVAL1]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL2:%.*]] = phi i64 [ [[IV_NEXT]], [[LOOP_INC]] ], [ 67, [[MIDDLE_BLOCK]] ]
+; VF4IC4-NEXT:    ret i64 [[RETVAL2]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop.inc ], [ 3, %entry ]
+  %gep.p1 = getelementptr inbounds i8, ptr %p1, i64 %iv
+  %ld1 = load i8, ptr %gep.p1, align 1
+  %gep.p2 = getelementptr inbounds i8, ptr %p2, i64 %iv
+  %ld2 = load i8, ptr %gep.p2, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.early.exit
+
+loop.inc:
+  %iv.next = add i64 %iv, 1
+  %exitcond = icmp ne i64 %iv.next, 67
+  br i1 %exitcond, label %loop, label %loop.end
+
+loop.early.exit:
+  %retval1 = phi i64 [ %iv, %loop ]
+  ret i64 %retval1
+
+loop.end:
+  %retval2 = phi i64 [ %iv.next, %loop.inc ]
+  ret i64 %retval2
+}
+
+; FIXME: Computes incorrect final IV when early exit is taken.
+define i64 @same_exit_block_pre_inc_use1_reverse() {
+; VF4IC4-LABEL: define i64 @same_exit_block_pre_inc_use1_reverse() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = sub i64 1023, [[INDEX]]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[TMP1]], i32 -3
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP2]], align 1
+; VF4IC4-NEXT:    [[REVERSE:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i8, ptr [[TMP3]], i32 0
+; VF4IC4-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[TMP4]], i32 -3
+; VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP5]], align 1
+; VF4IC4-NEXT:    [[REVERSE2:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD1]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; VF4IC4-NEXT:    [[TMP6:%.*]] = icmp ne <4 x i8> [[REVERSE]], [[REVERSE2]]
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP7:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP6]])
+; VF4IC4-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1008
+; VF4IC4-NEXT:    [[TMP9:%.*]] = or i1 [[TMP7]], [[TMP8]]
+; VF4IC4-NEXT:    br i1 [[TMP9]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP14:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP7]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 false, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[TMP10:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP6]], i1 true)
+; VF4IC4-NEXT:    [[TMP11:%.*]] = add i64 [[INDEX]], [[TMP10]]
+; VF4IC4-NEXT:    [[TMP12:%.*]] = sub i64 1023, [[TMP11]]
+; VF4IC4-NEXT:    br label [[LOOP_END]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 15, [[MIDDLE_BLOCK]] ], [ 1023, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_P1:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[GEP_P1]], align 1
+; VF4IC4-NEXT:    [[GEP_P2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD2:%.*]] = load i8, ptr [[GEP_P2]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], -1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp eq i64 [[IV_NEXT]], 0
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP_END]], label [[LOOP]], !llvm.loop [[LOOP15:![0-9]+]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL:%.*]] = phi i64 [ [[IV]], [[LOOP]] ], [ 1024, [[LOOP_INC]] ], [ 1024, [[MIDDLE_BLOCK]] ], [ [[TMP12]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i64 [[RETVAL]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop.inc ], [ 1023, %entry ]
+  %gep.p1 = getelementptr inbounds i8, ptr %p1, i64 %iv
+  %ld1 = load i8, ptr %gep.p1, align 1
+  %gep.p2 = getelementptr inbounds i8, ptr %p2, i64 %iv
+  %ld2 = load i8, ptr %gep.p2, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %iv.next = add i64 %iv, -1
+  %exitcond = icmp eq i64 %iv.next, 0
+  br i1 %exitcond, label %loop.end, label %loop
+
+loop.end:
+  %retval = phi i64 [ %iv, %loop ], [ 1024, %loop.inc ]
+  ret i64 %retval
+}
+
+; FIXME: Extracts incorrect lane if early exit is taken.
+define i8 @same_exit_block_use_loaded_value() {
+; VF4IC4-LABEL: define i8 @same_exit_block_use_loaded_value() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[INDEX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP1]], align 1
+; VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[INDEX]]
+; VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i32 0
+; VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP3]], align 1
+; VF4IC4-NEXT:    [[TMP4:%.*]] = icmp ne <4 x i8> [[WIDE_LOAD]], [[WIDE_LOAD1]]
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP5:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP4]])
+; VF4IC4-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1024
+; VF4IC4-NEXT:    [[TMP7:%.*]] = or i1 [[TMP5]], [[TMP6]]
+; VF4IC4-NEXT:    br i1 [[TMP7]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP16:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP5]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 true, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[FIRST_ACTIVE_LANE:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP4]], i1 true)
+; VF4IC4-NEXT:    [[EARLY_EXIT_VALUE:%.*]] = extractelement <4 x i8> [[WIDE_LOAD]], i64 [[FIRST_ACTIVE_LANE]]
+; VF4IC4-NEXT:    br label [[LOOP_END]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 1024, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_P1:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[GEP_P1]], align 1
+; VF4IC4-NEXT:    [[GEP_P2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD2:%.*]] = load i8, ptr [[GEP_P2]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP_END]], label [[LOOP]], !llvm.loop [[LOOP17:![0-9]+]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL:%.*]] = phi i8 [ [[LD1]], [[LOOP]] ], [ -1, [[LOOP_INC]] ], [ -1, [[MIDDLE_BLOCK]] ], [ [[EARLY_EXIT_VALUE]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i8 [[RETVAL]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop.inc ], [ 0, %entry ]
+  %gep.p1 = getelementptr inbounds i8, ptr %p1, i64 %iv
+  %ld1 = load i8, ptr %gep.p1, align 1
+  %gep.p2 = getelementptr inbounds i8, ptr %p2, i64 %iv
+  %ld2 = load i8, ptr %gep.p2, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %iv.next = add i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, 1024
+  br i1 %exitcond, label %loop.end, label %loop
+
+loop.end:
+  %retval = phi i8 [ %ld1, %loop ], [ -1, %loop.inc ]
+  ret i8 %retval
+}
+
+; FIXME: Extracts incorrect lane if early exit is taken.
+define i8 @same_exit_block_reverse_use_loaded_value() {
+; VF4IC4-LABEL: define i8 @same_exit_block_reverse_use_loaded_value() {
+; VF4IC4-NEXT:  entry:
+; VF4IC4-NEXT:    [[P1:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    [[P2:%.*]] = alloca [1024 x i8], align 1
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P1]], i64 1024)
+; VF4IC4-NEXT:    call void @init_mem(ptr [[P2]], i64 1024)
+; VF4IC4-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; VF4IC4:       vector.ph:
+; VF4IC4-NEXT:    br label [[VECTOR_BODY:%.*]]
+; VF4IC4:       vector.body:
+; VF4IC4-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; VF4IC4-NEXT:    [[OFFSET_IDX:%.*]] = sub i64 1023, [[INDEX]]
+; VF4IC4-NEXT:    [[TMP0:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i8, ptr [[TMP0]], i32 0
+; VF4IC4-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i8, ptr [[TMP1]], i32 -3
+; VF4IC4-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i8>, ptr [[TMP2]], align 1
+; VF4IC4-NEXT:    [[REVERSE:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; VF4IC4-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[OFFSET_IDX]]
+; VF4IC4-NEXT:    [[TMP4:%.*]] = getelementptr inbounds i8, ptr [[TMP3]], i32 0
+; VF4IC4-NEXT:    [[TMP5:%.*]] = getelementptr inbounds i8, ptr [[TMP4]], i32 -3
+; VF4IC4-NEXT:    [[WIDE_LOAD1:%.*]] = load <4 x i8>, ptr [[TMP5]], align 1
+; VF4IC4-NEXT:    [[REVERSE2:%.*]] = shufflevector <4 x i8> [[WIDE_LOAD1]], <4 x i8> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; VF4IC4-NEXT:    [[TMP6:%.*]] = icmp ne <4 x i8> [[REVERSE]], [[REVERSE2]]
+; VF4IC4-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; VF4IC4-NEXT:    [[TMP7:%.*]] = call i1 @llvm.vector.reduce.or.v4i1(<4 x i1> [[TMP6]])
+; VF4IC4-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1008
+; VF4IC4-NEXT:    [[TMP9:%.*]] = or i1 [[TMP7]], [[TMP8]]
+; VF4IC4-NEXT:    br i1 [[TMP9]], label [[MIDDLE_SPLIT:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP18:![0-9]+]]
+; VF4IC4:       middle.split:
+; VF4IC4-NEXT:    br i1 [[TMP7]], label [[VECTOR_EARLY_EXIT:%.*]], label [[MIDDLE_BLOCK:%.*]]
+; VF4IC4:       middle.block:
+; VF4IC4-NEXT:    br i1 false, label [[LOOP_END:%.*]], label [[SCALAR_PH]]
+; VF4IC4:       vector.early.exit:
+; VF4IC4-NEXT:    [[FIRST_ACTIVE_LANE:%.*]] = call i64 @llvm.experimental.cttz.elts.i64.v4i1(<4 x i1> [[TMP6]], i1 true)
+; VF4IC4-NEXT:    [[EARLY_EXIT_VALUE:%.*]] = extractelement <4 x i8> [[REVERSE]], i64 [[FIRST_ACTIVE_LANE]]
+; VF4IC4-NEXT:    br label [[LOOP_END]]
+; VF4IC4:       scalar.ph:
+; VF4IC4-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 15, [[MIDDLE_BLOCK]] ], [ 1023, [[ENTRY:%.*]] ]
+; VF4IC4-NEXT:    br label [[LOOP:%.*]]
+; VF4IC4:       loop:
+; VF4IC4-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[LOOP_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
+; VF4IC4-NEXT:    [[GEP_P1:%.*]] = getelementptr inbounds i8, ptr [[P1]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD1:%.*]] = load i8, ptr [[GEP_P1]], align 1
+; VF4IC4-NEXT:    [[GEP_P2:%.*]] = getelementptr inbounds i8, ptr [[P2]], i64 [[IV]]
+; VF4IC4-NEXT:    [[LD2:%.*]] = load i8, ptr [[GEP_P2]], align 1
+; VF4IC4-NEXT:    [[CMP3:%.*]] = icmp eq i8 [[LD1]], [[LD2]]
+; VF4IC4-NEXT:    br i1 [[CMP3]], label [[LOOP_INC]], label [[LOOP_END]]
+; VF4IC4:       loop.inc:
+; VF4IC4-NEXT:    [[IV_NEXT]] = add i64 [[IV]], -1
+; VF4IC4-NEXT:    [[EXITCOND:%.*]] = icmp eq i64 [[IV_NEXT]], 0
+; VF4IC4-NEXT:    br i1 [[EXITCOND]], label [[LOOP_END]], label [[LOOP]], !llvm.loop [[LOOP19:![0-9]+]]
+; VF4IC4:       loop.end:
+; VF4IC4-NEXT:    [[RETVAL:%.*]] = phi i8 [ [[LD1]], [[LOOP]] ], [ -1, [[LOOP_INC]] ], [ -1, [[MIDDLE_BLOCK]] ], [ [[EARLY_EXIT_VALUE]], [[VECTOR_EARLY_EXIT]] ]
+; VF4IC4-NEXT:    ret i8 [[RETVAL]]
+;
+entry:
+  %p1 = alloca [1024 x i8]
+  %p2 = alloca [1024 x i8]
+  call void @init_mem(ptr %p1, i64 1024)
+  call void @init_mem(ptr %p2, i64 1024)
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop.inc ], [ 1023, %entry ]
+  %gep.p1 = getelementptr inbounds i8, ptr %p1, i64 %iv
+  %ld1 = load i8, ptr %gep.p1, align 1
+  %gep.p2 = getelementptr inbounds i8, ptr %p2, i64 %iv
+  %ld2 = load i8, ptr %gep.p2, align 1
+  %cmp3 = icmp eq i8 %ld1, %ld2
+  br i1 %cmp3, label %loop.inc, label %loop.end
+
+loop.inc:
+  %iv.next = add i64 %iv, -1
+  %exitcond = icmp eq i64 %iv.next, 0
+  br i1 %exitcond, label %loop.end, label %loop
+
+loop.end:
+  %retval = phi i8 [ %ld1, %loop ], [ -1, %loop.inc ]
+  ret i8 %retval
+}


        


More information about the llvm-commits mailing list