[LV] Add tests for speculatively loading ptrs with UB/poison ops.

Test cases for #142957.

Author: fhahn

llvm/test/Transforms/LoopVectorize/load-deref-pred-poison-ub-ops-feeding-pointer.ll

@@ -0,0 +1,386 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --filter-out-after "scalar.ph:" --version 5
+; RUN: opt -p loop-vectorize -force-widen-divrem-via-safe-divisor=false -force-vector-width=2 -S %s | FileCheck %s
+
+target datalayout="p:16:16"
+
+@src = global [16 x i64] zeroinitializer
+
+; Test cases for https://github.com/llvm/llvm-project/issues/142957
+
+; FIXME: Cannot speculatively execute %l, because %div may trigger UB and must be
+; predicated.
+define void @ptr_depends_on_sdiv(ptr noalias %dst, i16 noundef %off) {
+; CHECK-LABEL: define void @ptr_depends_on_sdiv(
+; CHECK-SAME: ptr noalias [[DST:%.*]], i16 noundef [[OFF:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE4:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 9, i16 10>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE4]] ]
+; CHECK-NEXT:    [[DOTCAST:%.*]] = trunc i32 [[INDEX]] to i16
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i16 9, [[DOTCAST]]
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq <2 x i16> [[VEC_IND]], splat (i16 10)
+; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x i1> [[TMP0]], i32 0
+; CHECK-NEXT:    br i1 [[TMP6]], label %[[PRED_SDIV_IF:.*]], label %[[PRED_SDIV_CONTINUE:.*]]
+; CHECK:       [[PRED_SDIV_IF]]:
+; CHECK-NEXT:    [[TMP2:%.*]] = sdiv i16 24316, [[OFF]]
+; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE]]
+; CHECK:       [[PRED_SDIV_CONTINUE]]:
+; CHECK-NEXT:    [[TMP3:%.*]] = phi i16 [ poison, %[[VECTOR_BODY]] ], [ [[TMP2]], %[[PRED_SDIV_IF]] ]
+; CHECK-NEXT:    [[TMP14:%.*]] = extractelement <2 x i1> [[TMP0]], i32 1
+; CHECK-NEXT:    br i1 [[TMP14]], label %[[PRED_SDIV_IF1:.*]], label %[[PRED_SDIV_CONTINUE2:.*]]
+; CHECK:       [[PRED_SDIV_IF1]]:
+; CHECK-NEXT:    [[TMP18:%.*]] = sdiv i16 24316, [[OFF]]
+; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE2]]
+; CHECK:       [[PRED_SDIV_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP13:%.*]] = add i16 [[OFFSET_IDX]], 16383
+; CHECK-NEXT:    [[TMP7:%.*]] = shl i16 [[TMP3]], 14
+; CHECK-NEXT:    [[TMP8:%.*]] = sub i16 [[TMP13]], [[TMP7]]
+; CHECK-NEXT:    [[TMP20:%.*]] = getelementptr i64, ptr @src, i16 [[TMP8]]
+; CHECK-NEXT:    [[TMP21:%.*]] = getelementptr i64, ptr [[TMP20]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i64>, ptr [[TMP21]], align 1
+; CHECK-NEXT:    [[TMP19:%.*]] = extractelement <2 x i1> [[TMP0]], i32 0
+; CHECK-NEXT:    br i1 [[TMP19]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP10:%.*]] = add i16 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP10]]
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 0
+; CHECK-NEXT:    store i64 [[TMP9]], ptr [[TMP11]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = extractelement <2 x i1> [[TMP0]], i32 1
+; CHECK-NEXT:    br i1 [[TMP12]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_IF3]]:
+; CHECK-NEXT:    [[TMP16:%.*]] = add i16 [[OFFSET_IDX]], 1
+; CHECK-NEXT:    [[TMP17:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP16]]
+; CHECK-NEXT:    [[TMP15:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 1
+; CHECK-NEXT:    store i64 [[TMP15]], ptr [[TMP17]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_CONTINUE4]]:
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    br i1 true, label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br i1 true, [[EXIT:label %.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i16 [ 9, %entry ], [ %iv.next, %loop.latch ]
+  %cmp1 = icmp eq i16 %iv, 10
+  br i1 %cmp1, label %if.then, label %loop.latch
+
+if.then:
+  %div = sdiv i16 24316, %off
+  %add.iv = add i16 %iv, 16383
+  %s = shl i16 %div, 14
+  %sub6 = sub i16 %add.iv, %s
+  %gep.src = getelementptr inbounds i64, ptr @src, i16 %sub6
+  %l = load i64, ptr %gep.src, align 1
+  %gep.dst = getelementptr inbounds i64, ptr %dst, i16 %iv
+  store i64 %l, ptr %gep.dst, align 1
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i16 %iv, 1
+  %ec = icmp eq i16 %iv.next, 11
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  ret void
+}
+
+; FIXME: Cannot speculatively execute %l, because %off may be poison.
+define void @ptr_depends_on_possibly_poison_value(ptr noalias %dst, i16 %off) {
+; CHECK-LABEL: define void @ptr_depends_on_possibly_poison_value(
+; CHECK-SAME: ptr noalias [[DST:%.*]], i16 [[OFF:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP0:%.*]] = sub i16 1, [[OFF]]
+; CHECK-NEXT:    [[TMP1:%.*]] = add i16 [[TMP0]], [[OFF]]
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE2:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 9, i16 10>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE2]] ]
+; CHECK-NEXT:    [[DOTCAST:%.*]] = trunc i32 [[INDEX]] to i16
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i16 9, [[DOTCAST]]
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq <2 x i16> [[VEC_IND]], splat (i16 10)
+; CHECK-NEXT:    [[TMP3:%.*]] = add i16 [[OFFSET_IDX]], [[TMP1]]
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr @src, i16 [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i64, ptr [[TMP4]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i64>, ptr [[TMP5]], align 1
+; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP6]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = add i16 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP7]]
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 0
+; CHECK-NEXT:    store i64 [[TMP9]], ptr [[TMP8]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP10]], label %[[PRED_STORE_IF1:.*]], label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_IF1]]:
+; CHECK-NEXT:    [[TMP11:%.*]] = add i16 [[OFFSET_IDX]], 1
+; CHECK-NEXT:    [[TMP12:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP11]]
+; CHECK-NEXT:    [[TMP13:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 1
+; CHECK-NEXT:    store i64 [[TMP13]], ptr [[TMP12]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_CONTINUE2]]:
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    br i1 true, label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br i1 true, [[EXIT:label %.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i16 [ 9, %entry ], [ %iv.next, %loop.latch ]
+  %cmp1 = icmp eq i16 %iv, 10
+  br i1 %cmp1, label %if.then, label %loop.latch
+
+if.then:
+  %sub = sub i16 1, %off
+  %add = add i16 %sub, %off
+  %add.iv = add i16 %iv, %add
+  %gep.src = getelementptr inbounds i64, ptr @src, i16 %add.iv
+  %l = load i64, ptr %gep.src, align 1
+  %gep.dst = getelementptr inbounds i64, ptr %dst, i16 %iv
+  store i64 %l, ptr %gep.dst, align 1
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i16 %iv, 1
+  %ec = icmp eq i16 %iv.next, 11
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  ret void
+}
+
+define void @ptr_doesnt_depend_on_poison_or_ub(ptr noalias %dst, i16 noundef %off) {
+; CHECK-LABEL: define void @ptr_doesnt_depend_on_poison_or_ub(
+; CHECK-SAME: ptr noalias [[DST:%.*]], i16 noundef [[OFF:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP0:%.*]] = sub i16 1, [[OFF]]
+; CHECK-NEXT:    [[TMP1:%.*]] = add i16 [[TMP0]], [[OFF]]
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE2:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 9, i16 10>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE2]] ]
+; CHECK-NEXT:    [[DOTCAST:%.*]] = trunc i32 [[INDEX]] to i16
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i16 9, [[DOTCAST]]
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq <2 x i16> [[VEC_IND]], splat (i16 10)
+; CHECK-NEXT:    [[TMP3:%.*]] = add i16 [[OFFSET_IDX]], [[TMP1]]
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr @src, i16 [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i64, ptr [[TMP4]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i64>, ptr [[TMP5]], align 1
+; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP6]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = add i16 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP7]]
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 0
+; CHECK-NEXT:    store i64 [[TMP9]], ptr [[TMP8]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP10]], label %[[PRED_STORE_IF1:.*]], label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_IF1]]:
+; CHECK-NEXT:    [[TMP11:%.*]] = add i16 [[OFFSET_IDX]], 1
+; CHECK-NEXT:    [[TMP12:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP11]]
+; CHECK-NEXT:    [[TMP13:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 1
+; CHECK-NEXT:    store i64 [[TMP13]], ptr [[TMP12]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_CONTINUE2]]:
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    br i1 true, label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br i1 true, [[EXIT:label %.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i16 [ 9, %entry ], [ %iv.next, %loop.latch ]
+  %cmp1 = icmp eq i16 %iv, 10
+  br i1 %cmp1, label %if.then, label %loop.latch
+
+if.then:
+  %sub = sub i16 1, %off
+  %add = add i16 %sub, %off
+  %add.iv = add i16 %iv, %add
+  %gep.src = getelementptr inbounds i64, ptr @src, i16 %add.iv
+  %l = load i64, ptr %gep.src, align 1
+  %gep.dst = getelementptr inbounds i64, ptr %dst, i16 %iv
+  store i64 %l, ptr %gep.dst, align 1
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i16 %iv, 1
+  %ec = icmp eq i16 %iv.next, 11
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  ret void
+}
+
+; FIXME: Cannot speculatively execute %l, because %off may be poison.
+define void @ptr_depends_on_possibly_poison_value_from_load(ptr noalias %dst) {
+; CHECK-LABEL: define void @ptr_depends_on_possibly_poison_value_from_load(
+; CHECK-SAME: ptr noalias [[DST:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE2:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 9, i16 10>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE2]] ]
+; CHECK-NEXT:    [[DOTCAST:%.*]] = trunc i32 [[INDEX]] to i16
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i16 9, [[DOTCAST]]
+; CHECK-NEXT:    [[TMP0:%.*]] = load i16, ptr @src, align 1
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq <2 x i16> [[VEC_IND]], splat (i16 10)
+; CHECK-NEXT:    [[TMP2:%.*]] = sub i16 1, [[TMP0]]
+; CHECK-NEXT:    [[TMP3:%.*]] = add i16 [[TMP2]], [[TMP0]]
+; CHECK-NEXT:    [[TMP4:%.*]] = add i16 [[OFFSET_IDX]], [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i64, ptr @src, i16 [[TMP4]]
+; CHECK-NEXT:    [[TMP6:%.*]] = getelementptr i64, ptr [[TMP5]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i64>, ptr [[TMP6]], align 1
+; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x i1> [[TMP1]], i32 0
+; CHECK-NEXT:    br i1 [[TMP7]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP8:%.*]] = add i16 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP8]]
+; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 0
+; CHECK-NEXT:    store i64 [[TMP10]], ptr [[TMP9]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP11:%.*]] = extractelement <2 x i1> [[TMP1]], i32 1
+; CHECK-NEXT:    br i1 [[TMP11]], label %[[PRED_STORE_IF1:.*]], label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_IF1]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = add i16 [[OFFSET_IDX]], 1
+; CHECK-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP12]]
+; CHECK-NEXT:    [[TMP14:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 1
+; CHECK-NEXT:    store i64 [[TMP14]], ptr [[TMP13]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_CONTINUE2]]:
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    br i1 true, label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br i1 true, [[EXIT:label %.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i16 [ 9, %entry ], [ %iv.next, %loop.latch ]
+  %off = load i16, ptr @src, align 1
+  %cmp1 = icmp eq i16 %iv, 10
+  br i1 %cmp1, label %if.then, label %loop.latch
+
+if.then:
+  %sub = sub i16 1, %off
+  %add = add i16 %sub, %off
+  %add.iv = add i16 %iv, %add
+  %gep.src = getelementptr inbounds i64, ptr @src, i16 %add.iv
+  %l = load i64, ptr %gep.src, align 1
+  %gep.dst = getelementptr inbounds i64, ptr %dst, i16 %iv
+  store i64 %l, ptr %gep.dst, align 1
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i16 %iv, 1
+  %ec = icmp eq i16 %iv.next, 11
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  ret void
+}
+
+; Can speculatively execute %l, because %off cannot be poison due to !noundef.
+define void @ptr_depends_on_noundef_load(ptr noalias %dst) {
+; CHECK-LABEL: define void @ptr_depends_on_noundef_load(
+; CHECK-SAME: ptr noalias [[DST:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i32 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE2:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 9, i16 10>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE2]] ]
+; CHECK-NEXT:    [[DOTCAST:%.*]] = trunc i32 [[INDEX]] to i16
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i16 9, [[DOTCAST]]
+; CHECK-NEXT:    [[TMP0:%.*]] = load i16, ptr @src, align 1, !noundef [[META10:![0-9]+]]
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq <2 x i16> [[VEC_IND]], splat (i16 10)
+; CHECK-NEXT:    [[TMP2:%.*]] = sub i16 1, [[TMP0]]
+; CHECK-NEXT:    [[TMP3:%.*]] = add i16 [[TMP2]], [[TMP0]]
+; CHECK-NEXT:    [[TMP4:%.*]] = add i16 [[OFFSET_IDX]], [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i64, ptr @src, i16 [[TMP4]]
+; CHECK-NEXT:    [[TMP6:%.*]] = getelementptr i64, ptr [[TMP5]], i32 0
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <2 x i64>, ptr [[TMP6]], align 1
+; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x i1> [[TMP1]], i32 0
+; CHECK-NEXT:    br i1 [[TMP7]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP8:%.*]] = add i16 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP8]]
+; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 0
+; CHECK-NEXT:    store i64 [[TMP10]], ptr [[TMP9]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP11:%.*]] = extractelement <2 x i1> [[TMP1]], i32 1
+; CHECK-NEXT:    br i1 [[TMP11]], label %[[PRED_STORE_IF1:.*]], label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_IF1]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = add i16 [[OFFSET_IDX]], 1
+; CHECK-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i64, ptr [[DST]], i16 [[TMP12]]
+; CHECK-NEXT:    [[TMP14:%.*]] = extractelement <2 x i64> [[WIDE_LOAD]], i32 1
+; CHECK-NEXT:    store i64 [[TMP14]], ptr [[TMP13]], align 1
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_CONTINUE2]]:
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 2
+; CHECK-NEXT:    br i1 true, label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP11:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br i1 true, [[EXIT:label %.*]], label %[[SCALAR_PH]]
+; CHECK:       [[SCALAR_PH]]:
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i16 [ 9, %entry ], [ %iv.next, %loop.latch ]
+  %off = load i16, ptr @src, align 1, !noundef !{}
+  %cmp1 = icmp eq i16 %iv, 10
+  br i1 %cmp1, label %if.then, label %loop.latch
+
+if.then:
+  %sub = sub i16 1, %off
+  %add = add i16 %sub, %off
+  %add.iv = add i16 %iv, %add
+  %gep.src = getelementptr inbounds i64, ptr @src, i16 %add.iv
+  %l = load i64, ptr %gep.src, align 1
+  %gep.dst = getelementptr inbounds i64, ptr %dst, i16 %iv
+  store i64 %l, ptr %gep.dst, align 1
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i16 %iv, 1
+  %ec = icmp eq i16 %iv.next, 11
+  br i1 %ec, label %exit, label %loop.header
+
+exit:
+  ret void
+}