[llvm-branch-commits] [llvm] 0129cd5 - Use deref facts derived from minimum object size of allocations

Philip Reames via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Thu Dec 3 15:05:38 PST 2020


Author: Philip Reames
Date: 2020-12-03T15:01:14-08:00
New Revision: 0129cd503575076556935a16f458b0a3c2e30646

URL: https://github.com/llvm/llvm-project/commit/0129cd503575076556935a16f458b0a3c2e30646
DIFF: https://github.com/llvm/llvm-project/commit/0129cd503575076556935a16f458b0a3c2e30646.diff

LOG: Use deref facts derived from minimum object size of allocations

This change should be fairly straight forward. If we've reached a call, check to see if we can tell the result is dereferenceable from information about the minimum object size returned by the call.

To control compile time impact, I'm only adding the call for base facts in the routine. getObjectSize can also do recursive reasoning, and we don't want that general capability here.

As a follow up patch (without separate review), I will plumb through the missing TLI parameter. That will have the effect of extending this to known libcalls - malloc, new, and the like - whereas currently this only covers calls with the explicit allocsize attribute.

Differential Revision: https://reviews.llvm.org/D90341

Added: 
    

Modified: 
    llvm/lib/Analysis/Loads.cpp
    llvm/test/Transforms/LoopVectorize/X86/load-deref-pred.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index 2ca35a4344ec..8f373f70f216 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -12,7 +12,9 @@
 
 #include "llvm/Analysis/Loads.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/CaptureTracking.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/MemoryBuiltins.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
 #include "llvm/Analysis/ValueTracking.h"
@@ -107,11 +109,50 @@ static bool isDereferenceableAndAlignedPointer(
     return isDereferenceableAndAlignedPointer(ASC->getOperand(0), Alignment,
                                               Size, DL, CtxI, DT, Visited, MaxDepth);
 
-  if (const auto *Call = dyn_cast<CallBase>(V))
+  if (const auto *Call = dyn_cast<CallBase>(V)) {
     if (auto *RP = getArgumentAliasingToReturnedPointer(Call, true))
       return isDereferenceableAndAlignedPointer(RP, Alignment, Size, DL, CtxI,
                                                 DT, Visited, MaxDepth);
 
+    // If we have a call we can't recurse through, check to see if this is an
+    // allocation function for which we can establish an minimum object size.
+    // Such a minimum object size is analogous to a deref_or_null attribute in
+    // that we still need to prove the result non-null at point of use.
+    // NOTE: We can only use the object size as a base fact as we a) need to
+    // prove alignment too, and b) don't want the compile time impact of a
+    // separate recursive walk.
+    ObjectSizeOpts Opts;
+    // TODO: It may be okay to round to align, but that would imply that
+    // accessing slightly out of bounds was legal, and we're currently
+    // inconsistent about that.  For the moment, be conservative.
+    Opts.RoundToAlign = false;
+    Opts.NullIsUnknownSize = true;
+    uint64_t ObjSize;
+    // TODO: Plumb through TLI so that malloc routines and such working.
+    if (getObjectSize(V, ObjSize, DL, nullptr, Opts)) {
+      APInt KnownDerefBytes(Size.getBitWidth(), ObjSize);
+      if (KnownDerefBytes.getBoolValue() && KnownDerefBytes.uge(Size) &&
+          isKnownNonZero(V, DL, 0, nullptr, CtxI, DT) &&
+          // TODO: We're currently inconsistent about whether deref(N) is a
+          // global fact or a point in time fact.  Once D61652 eventually
+          // lands, this check will be restricted to the point in time
+          // variant. For that variant, we need to prove that object hasn't
+          // been conditionally freed before ontext instruction - if it has, we
+          // might be hoisting over the inverse conditional and creating a
+          // dynamic use after free. 
+          !PointerMayBeCapturedBefore(V, true, true, CtxI, DT, true)) {
+        // As we recursed through GEPs to get here, we've incrementally
+        // checked that each step advanced by a multiple of the alignment. If
+        // our base is properly aligned, then the original offset accessed
+        // must also be. 
+        Type *Ty = V->getType();
+        assert(Ty->isSized() && "must be sized");
+        APInt Offset(DL.getTypeStoreSizeInBits(Ty), 0);
+        return isAligned(V, Offset, Alignment, DL);
+      }
+    }
+  }
+
   // If we don't know, assume the worst.
   return false;
 }

diff  --git a/llvm/test/Transforms/LoopVectorize/X86/load-deref-pred.ll b/llvm/test/Transforms/LoopVectorize/X86/load-deref-pred.ll
index 7937c71b7705..167285707e02 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/load-deref-pred.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/load-deref-pred.ll
@@ -8,7 +8,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ;; We don't need a masked.load for this due to deref facts, and can instead
 ;; use a plain vector load.
 
-declare void @init(i32*)
+declare void @init(i32* nocapture nofree)
 
 ;; For ease of explanation, this one demonstrates
 ;; with a range check, but there are better lowering options specifically for
@@ -2209,3 +2209,525 @@ loop_exit:
   ret i32 %accum.next
 }
 
+
+;; Model a custom allocate which allocates in chunks of 8 bytes
+declare align 8 dereferenceable_or_null(8) i8* @my_alloc(i32) allocsize(0)
+declare align 8 dereferenceable_or_null(8) i8* @my_array_alloc(i32, i32) allocsize(0, 1)
+
+define i32 @test_allocsize(i64 %len, i1* %test_base) {
+; CHECK-LABEL: @test_allocsize(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ALLOCATION:%.*]] = call nonnull i8* @my_alloc(i32 16384)
+; CHECK-NEXT:    [[BASE:%.*]] = bitcast i8* [[ALLOCATION]] to i32*
+; CHECK-NEXT:    call void @init(i32* [[BASE]])
+; 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 i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP80:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI1:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP81:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI2:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP82:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI3:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP83:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = add i64 [[INDEX]], 2
+; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[INDEX]], 3
+; CHECK-NEXT:    [[TMP4:%.*]] = add i64 [[INDEX]], 4
+; CHECK-NEXT:    [[TMP5:%.*]] = add i64 [[INDEX]], 5
+; CHECK-NEXT:    [[TMP6:%.*]] = add i64 [[INDEX]], 6
+; CHECK-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], 7
+; CHECK-NEXT:    [[TMP8:%.*]] = add i64 [[INDEX]], 8
+; CHECK-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], 9
+; CHECK-NEXT:    [[TMP10:%.*]] = add i64 [[INDEX]], 10
+; CHECK-NEXT:    [[TMP11:%.*]] = add i64 [[INDEX]], 11
+; CHECK-NEXT:    [[TMP12:%.*]] = add i64 [[INDEX]], 12
+; CHECK-NEXT:    [[TMP13:%.*]] = add i64 [[INDEX]], 13
+; CHECK-NEXT:    [[TMP14:%.*]] = add i64 [[INDEX]], 14
+; CHECK-NEXT:    [[TMP15:%.*]] = add i64 [[INDEX]], 15
+; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE:%.*]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP17:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP18:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP19:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP3]]
+; CHECK-NEXT:    [[TMP20:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP4]]
+; CHECK-NEXT:    [[TMP21:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP5]]
+; CHECK-NEXT:    [[TMP22:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP6]]
+; CHECK-NEXT:    [[TMP23:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP7]]
+; CHECK-NEXT:    [[TMP24:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP8]]
+; CHECK-NEXT:    [[TMP25:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP9]]
+; CHECK-NEXT:    [[TMP26:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP10]]
+; CHECK-NEXT:    [[TMP27:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP11]]
+; CHECK-NEXT:    [[TMP28:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP12]]
+; CHECK-NEXT:    [[TMP29:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP13]]
+; CHECK-NEXT:    [[TMP30:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP14]]
+; CHECK-NEXT:    [[TMP31:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP15]]
+; CHECK-NEXT:    [[TMP32:%.*]] = load i1, i1* [[TMP16]], align 1
+; CHECK-NEXT:    [[TMP33:%.*]] = load i1, i1* [[TMP17]], align 1
+; CHECK-NEXT:    [[TMP34:%.*]] = load i1, i1* [[TMP18]], align 1
+; CHECK-NEXT:    [[TMP35:%.*]] = load i1, i1* [[TMP19]], align 1
+; CHECK-NEXT:    [[TMP36:%.*]] = insertelement <4 x i1> undef, i1 [[TMP32]], i32 0
+; CHECK-NEXT:    [[TMP37:%.*]] = insertelement <4 x i1> [[TMP36]], i1 [[TMP33]], i32 1
+; CHECK-NEXT:    [[TMP38:%.*]] = insertelement <4 x i1> [[TMP37]], i1 [[TMP34]], i32 2
+; CHECK-NEXT:    [[TMP39:%.*]] = insertelement <4 x i1> [[TMP38]], i1 [[TMP35]], i32 3
+; CHECK-NEXT:    [[TMP40:%.*]] = load i1, i1* [[TMP20]], align 1
+; CHECK-NEXT:    [[TMP41:%.*]] = load i1, i1* [[TMP21]], align 1
+; CHECK-NEXT:    [[TMP42:%.*]] = load i1, i1* [[TMP22]], align 1
+; CHECK-NEXT:    [[TMP43:%.*]] = load i1, i1* [[TMP23]], align 1
+; CHECK-NEXT:    [[TMP44:%.*]] = insertelement <4 x i1> undef, i1 [[TMP40]], i32 0
+; CHECK-NEXT:    [[TMP45:%.*]] = insertelement <4 x i1> [[TMP44]], i1 [[TMP41]], i32 1
+; CHECK-NEXT:    [[TMP46:%.*]] = insertelement <4 x i1> [[TMP45]], i1 [[TMP42]], i32 2
+; CHECK-NEXT:    [[TMP47:%.*]] = insertelement <4 x i1> [[TMP46]], i1 [[TMP43]], i32 3
+; CHECK-NEXT:    [[TMP48:%.*]] = load i1, i1* [[TMP24]], align 1
+; CHECK-NEXT:    [[TMP49:%.*]] = load i1, i1* [[TMP25]], align 1
+; CHECK-NEXT:    [[TMP50:%.*]] = load i1, i1* [[TMP26]], align 1
+; CHECK-NEXT:    [[TMP51:%.*]] = load i1, i1* [[TMP27]], align 1
+; CHECK-NEXT:    [[TMP52:%.*]] = insertelement <4 x i1> undef, i1 [[TMP48]], i32 0
+; CHECK-NEXT:    [[TMP53:%.*]] = insertelement <4 x i1> [[TMP52]], i1 [[TMP49]], i32 1
+; CHECK-NEXT:    [[TMP54:%.*]] = insertelement <4 x i1> [[TMP53]], i1 [[TMP50]], i32 2
+; CHECK-NEXT:    [[TMP55:%.*]] = insertelement <4 x i1> [[TMP54]], i1 [[TMP51]], i32 3
+; CHECK-NEXT:    [[TMP56:%.*]] = load i1, i1* [[TMP28]], align 1
+; CHECK-NEXT:    [[TMP57:%.*]] = load i1, i1* [[TMP29]], align 1
+; CHECK-NEXT:    [[TMP58:%.*]] = load i1, i1* [[TMP30]], align 1
+; CHECK-NEXT:    [[TMP59:%.*]] = load i1, i1* [[TMP31]], align 1
+; CHECK-NEXT:    [[TMP60:%.*]] = insertelement <4 x i1> undef, i1 [[TMP56]], i32 0
+; CHECK-NEXT:    [[TMP61:%.*]] = insertelement <4 x i1> [[TMP60]], i1 [[TMP57]], i32 1
+; CHECK-NEXT:    [[TMP62:%.*]] = insertelement <4 x i1> [[TMP61]], i1 [[TMP58]], i32 2
+; CHECK-NEXT:    [[TMP63:%.*]] = insertelement <4 x i1> [[TMP62]], i1 [[TMP59]], i32 3
+; CHECK-NEXT:    [[TMP64:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP65:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP4]]
+; CHECK-NEXT:    [[TMP66:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP8]]
+; CHECK-NEXT:    [[TMP67:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP12]]
+; CHECK-NEXT:    [[TMP68:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 0
+; CHECK-NEXT:    [[TMP69:%.*]] = bitcast i32* [[TMP68]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, <4 x i32>* [[TMP69]], align 4
+; CHECK-NEXT:    [[TMP70:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 4
+; CHECK-NEXT:    [[TMP71:%.*]] = bitcast i32* [[TMP70]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD4:%.*]] = load <4 x i32>, <4 x i32>* [[TMP71]], align 4
+; CHECK-NEXT:    [[TMP72:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 8
+; CHECK-NEXT:    [[TMP73:%.*]] = bitcast i32* [[TMP72]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD5:%.*]] = load <4 x i32>, <4 x i32>* [[TMP73]], align 4
+; CHECK-NEXT:    [[TMP74:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 12
+; CHECK-NEXT:    [[TMP75:%.*]] = bitcast i32* [[TMP74]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD6:%.*]] = load <4 x i32>, <4 x i32>* [[TMP75]], align 4
+; CHECK-NEXT:    [[TMP76:%.*]] = xor <4 x i1> [[TMP39]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP77:%.*]] = xor <4 x i1> [[TMP47]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP78:%.*]] = xor <4 x i1> [[TMP55]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP79:%.*]] = xor <4 x i1> [[TMP63]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[PREDPHI:%.*]] = select <4 x i1> [[TMP39]], <4 x i32> [[WIDE_LOAD]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI7:%.*]] = select <4 x i1> [[TMP47]], <4 x i32> [[WIDE_LOAD4]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI8:%.*]] = select <4 x i1> [[TMP55]], <4 x i32> [[WIDE_LOAD5]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI9:%.*]] = select <4 x i1> [[TMP63]], <4 x i32> [[WIDE_LOAD6]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP80]] = add <4 x i32> [[VEC_PHI]], [[PREDPHI]]
+; CHECK-NEXT:    [[TMP81]] = add <4 x i32> [[VEC_PHI1]], [[PREDPHI7]]
+; CHECK-NEXT:    [[TMP82]] = add <4 x i32> [[VEC_PHI2]], [[PREDPHI8]]
+; CHECK-NEXT:    [[TMP83]] = add <4 x i32> [[VEC_PHI3]], [[PREDPHI9]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 16
+; CHECK-NEXT:    [[TMP84:%.*]] = icmp eq i64 [[INDEX_NEXT]], 4096
+; CHECK-NEXT:    br i1 [[TMP84]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], [[LOOP24:!llvm.loop !.*]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[BIN_RDX:%.*]] = add <4 x i32> [[TMP81]], [[TMP80]]
+; CHECK-NEXT:    [[BIN_RDX10:%.*]] = add <4 x i32> [[TMP82]], [[BIN_RDX]]
+; CHECK-NEXT:    [[BIN_RDX11:%.*]] = add <4 x i32> [[TMP83]], [[BIN_RDX10]]
+; CHECK-NEXT:    [[TMP85:%.*]] = call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> [[BIN_RDX11]])
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 4096, 4096
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[LOOP_EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 4096, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[TMP85]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LATCH:%.*]] ]
+; CHECK-NEXT:    [[ACCUM:%.*]] = phi i32 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[ACCUM_NEXT:%.*]], [[LATCH]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[TEST_ADDR:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[IV]]
+; CHECK-NEXT:    [[EARLYCND:%.*]] = load i1, i1* [[TEST_ADDR]], align 1
+; CHECK-NEXT:    br i1 [[EARLYCND]], label [[PRED:%.*]], label [[LATCH]]
+; CHECK:       pred:
+; CHECK-NEXT:    [[ADDR:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[IV]]
+; CHECK-NEXT:    [[VAL:%.*]] = load i32, i32* [[ADDR]], align 4
+; CHECK-NEXT:    br label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    [[VAL_PHI:%.*]] = phi i32 [ 0, [[LOOP]] ], [ [[VAL]], [[PRED]] ]
+; CHECK-NEXT:    [[ACCUM_NEXT]] = add i32 [[ACCUM]], [[VAL_PHI]]
+; CHECK-NEXT:    [[EXIT:%.*]] = icmp ugt i64 [[IV]], 4094
+; CHECK-NEXT:    br i1 [[EXIT]], label [[LOOP_EXIT]], label [[LOOP]], [[LOOP25:!llvm.loop !.*]]
+; CHECK:       loop_exit:
+; CHECK-NEXT:    [[ACCUM_NEXT_LCSSA:%.*]] = phi i32 [ [[ACCUM_NEXT]], [[LATCH]] ], [ [[TMP85]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i32 [[ACCUM_NEXT_LCSSA]]
+;
+entry:
+  %allocation = call nonnull i8* @my_alloc(i32 16384)
+  %base = bitcast i8* %allocation to i32*
+  call void @init(i32* %base)
+  br label %loop
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %latch ]
+  %accum = phi i32 [ 0, %entry ], [ %accum.next, %latch ]
+  %iv.next = add i64 %iv, 1
+  %test_addr = getelementptr inbounds i1, i1* %test_base, i64 %iv
+  %earlycnd = load i1, i1* %test_addr
+  br i1 %earlycnd, label %pred, label %latch
+pred:
+  %addr = getelementptr inbounds i32, i32* %base, i64 %iv
+  %val = load i32, i32* %addr
+  br label %latch
+latch:
+  %val.phi = phi i32 [0, %loop], [%val, %pred]
+  %accum.next = add i32 %accum, %val.phi
+  %exit = icmp ugt i64 %iv, 4094
+  br i1 %exit, label %loop_exit, label %loop
+
+loop_exit:
+  ret i32 %accum.next
+}
+
+
+define i32 @test_allocsize_array(i64 %len, i1* %test_base) {
+; CHECK-LABEL: @test_allocsize_array(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ALLOCATION:%.*]] = call nonnull i8* @my_array_alloc(i32 4096, i32 4)
+; CHECK-NEXT:    [[BASE:%.*]] = bitcast i8* [[ALLOCATION]] to i32*
+; CHECK-NEXT:    call void @init(i32* [[BASE]])
+; 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 i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP80:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI1:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP81:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI2:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP82:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI3:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP83:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = add i64 [[INDEX]], 2
+; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[INDEX]], 3
+; CHECK-NEXT:    [[TMP4:%.*]] = add i64 [[INDEX]], 4
+; CHECK-NEXT:    [[TMP5:%.*]] = add i64 [[INDEX]], 5
+; CHECK-NEXT:    [[TMP6:%.*]] = add i64 [[INDEX]], 6
+; CHECK-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], 7
+; CHECK-NEXT:    [[TMP8:%.*]] = add i64 [[INDEX]], 8
+; CHECK-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], 9
+; CHECK-NEXT:    [[TMP10:%.*]] = add i64 [[INDEX]], 10
+; CHECK-NEXT:    [[TMP11:%.*]] = add i64 [[INDEX]], 11
+; CHECK-NEXT:    [[TMP12:%.*]] = add i64 [[INDEX]], 12
+; CHECK-NEXT:    [[TMP13:%.*]] = add i64 [[INDEX]], 13
+; CHECK-NEXT:    [[TMP14:%.*]] = add i64 [[INDEX]], 14
+; CHECK-NEXT:    [[TMP15:%.*]] = add i64 [[INDEX]], 15
+; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE:%.*]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP17:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP18:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP19:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP3]]
+; CHECK-NEXT:    [[TMP20:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP4]]
+; CHECK-NEXT:    [[TMP21:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP5]]
+; CHECK-NEXT:    [[TMP22:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP6]]
+; CHECK-NEXT:    [[TMP23:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP7]]
+; CHECK-NEXT:    [[TMP24:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP8]]
+; CHECK-NEXT:    [[TMP25:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP9]]
+; CHECK-NEXT:    [[TMP26:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP10]]
+; CHECK-NEXT:    [[TMP27:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP11]]
+; CHECK-NEXT:    [[TMP28:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP12]]
+; CHECK-NEXT:    [[TMP29:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP13]]
+; CHECK-NEXT:    [[TMP30:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP14]]
+; CHECK-NEXT:    [[TMP31:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP15]]
+; CHECK-NEXT:    [[TMP32:%.*]] = load i1, i1* [[TMP16]], align 1
+; CHECK-NEXT:    [[TMP33:%.*]] = load i1, i1* [[TMP17]], align 1
+; CHECK-NEXT:    [[TMP34:%.*]] = load i1, i1* [[TMP18]], align 1
+; CHECK-NEXT:    [[TMP35:%.*]] = load i1, i1* [[TMP19]], align 1
+; CHECK-NEXT:    [[TMP36:%.*]] = insertelement <4 x i1> undef, i1 [[TMP32]], i32 0
+; CHECK-NEXT:    [[TMP37:%.*]] = insertelement <4 x i1> [[TMP36]], i1 [[TMP33]], i32 1
+; CHECK-NEXT:    [[TMP38:%.*]] = insertelement <4 x i1> [[TMP37]], i1 [[TMP34]], i32 2
+; CHECK-NEXT:    [[TMP39:%.*]] = insertelement <4 x i1> [[TMP38]], i1 [[TMP35]], i32 3
+; CHECK-NEXT:    [[TMP40:%.*]] = load i1, i1* [[TMP20]], align 1
+; CHECK-NEXT:    [[TMP41:%.*]] = load i1, i1* [[TMP21]], align 1
+; CHECK-NEXT:    [[TMP42:%.*]] = load i1, i1* [[TMP22]], align 1
+; CHECK-NEXT:    [[TMP43:%.*]] = load i1, i1* [[TMP23]], align 1
+; CHECK-NEXT:    [[TMP44:%.*]] = insertelement <4 x i1> undef, i1 [[TMP40]], i32 0
+; CHECK-NEXT:    [[TMP45:%.*]] = insertelement <4 x i1> [[TMP44]], i1 [[TMP41]], i32 1
+; CHECK-NEXT:    [[TMP46:%.*]] = insertelement <4 x i1> [[TMP45]], i1 [[TMP42]], i32 2
+; CHECK-NEXT:    [[TMP47:%.*]] = insertelement <4 x i1> [[TMP46]], i1 [[TMP43]], i32 3
+; CHECK-NEXT:    [[TMP48:%.*]] = load i1, i1* [[TMP24]], align 1
+; CHECK-NEXT:    [[TMP49:%.*]] = load i1, i1* [[TMP25]], align 1
+; CHECK-NEXT:    [[TMP50:%.*]] = load i1, i1* [[TMP26]], align 1
+; CHECK-NEXT:    [[TMP51:%.*]] = load i1, i1* [[TMP27]], align 1
+; CHECK-NEXT:    [[TMP52:%.*]] = insertelement <4 x i1> undef, i1 [[TMP48]], i32 0
+; CHECK-NEXT:    [[TMP53:%.*]] = insertelement <4 x i1> [[TMP52]], i1 [[TMP49]], i32 1
+; CHECK-NEXT:    [[TMP54:%.*]] = insertelement <4 x i1> [[TMP53]], i1 [[TMP50]], i32 2
+; CHECK-NEXT:    [[TMP55:%.*]] = insertelement <4 x i1> [[TMP54]], i1 [[TMP51]], i32 3
+; CHECK-NEXT:    [[TMP56:%.*]] = load i1, i1* [[TMP28]], align 1
+; CHECK-NEXT:    [[TMP57:%.*]] = load i1, i1* [[TMP29]], align 1
+; CHECK-NEXT:    [[TMP58:%.*]] = load i1, i1* [[TMP30]], align 1
+; CHECK-NEXT:    [[TMP59:%.*]] = load i1, i1* [[TMP31]], align 1
+; CHECK-NEXT:    [[TMP60:%.*]] = insertelement <4 x i1> undef, i1 [[TMP56]], i32 0
+; CHECK-NEXT:    [[TMP61:%.*]] = insertelement <4 x i1> [[TMP60]], i1 [[TMP57]], i32 1
+; CHECK-NEXT:    [[TMP62:%.*]] = insertelement <4 x i1> [[TMP61]], i1 [[TMP58]], i32 2
+; CHECK-NEXT:    [[TMP63:%.*]] = insertelement <4 x i1> [[TMP62]], i1 [[TMP59]], i32 3
+; CHECK-NEXT:    [[TMP64:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP65:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP4]]
+; CHECK-NEXT:    [[TMP66:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP8]]
+; CHECK-NEXT:    [[TMP67:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP12]]
+; CHECK-NEXT:    [[TMP68:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 0
+; CHECK-NEXT:    [[TMP69:%.*]] = bitcast i32* [[TMP68]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = load <4 x i32>, <4 x i32>* [[TMP69]], align 4
+; CHECK-NEXT:    [[TMP70:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 4
+; CHECK-NEXT:    [[TMP71:%.*]] = bitcast i32* [[TMP70]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD4:%.*]] = load <4 x i32>, <4 x i32>* [[TMP71]], align 4
+; CHECK-NEXT:    [[TMP72:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 8
+; CHECK-NEXT:    [[TMP73:%.*]] = bitcast i32* [[TMP72]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD5:%.*]] = load <4 x i32>, <4 x i32>* [[TMP73]], align 4
+; CHECK-NEXT:    [[TMP74:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 12
+; CHECK-NEXT:    [[TMP75:%.*]] = bitcast i32* [[TMP74]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_LOAD6:%.*]] = load <4 x i32>, <4 x i32>* [[TMP75]], align 4
+; CHECK-NEXT:    [[TMP76:%.*]] = xor <4 x i1> [[TMP39]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP77:%.*]] = xor <4 x i1> [[TMP47]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP78:%.*]] = xor <4 x i1> [[TMP55]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP79:%.*]] = xor <4 x i1> [[TMP63]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[PREDPHI:%.*]] = select <4 x i1> [[TMP39]], <4 x i32> [[WIDE_LOAD]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI7:%.*]] = select <4 x i1> [[TMP47]], <4 x i32> [[WIDE_LOAD4]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI8:%.*]] = select <4 x i1> [[TMP55]], <4 x i32> [[WIDE_LOAD5]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI9:%.*]] = select <4 x i1> [[TMP63]], <4 x i32> [[WIDE_LOAD6]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP80]] = add <4 x i32> [[VEC_PHI]], [[PREDPHI]]
+; CHECK-NEXT:    [[TMP81]] = add <4 x i32> [[VEC_PHI1]], [[PREDPHI7]]
+; CHECK-NEXT:    [[TMP82]] = add <4 x i32> [[VEC_PHI2]], [[PREDPHI8]]
+; CHECK-NEXT:    [[TMP83]] = add <4 x i32> [[VEC_PHI3]], [[PREDPHI9]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 16
+; CHECK-NEXT:    [[TMP84:%.*]] = icmp eq i64 [[INDEX_NEXT]], 4096
+; CHECK-NEXT:    br i1 [[TMP84]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], [[LOOP26:!llvm.loop !.*]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[BIN_RDX:%.*]] = add <4 x i32> [[TMP81]], [[TMP80]]
+; CHECK-NEXT:    [[BIN_RDX10:%.*]] = add <4 x i32> [[TMP82]], [[BIN_RDX]]
+; CHECK-NEXT:    [[BIN_RDX11:%.*]] = add <4 x i32> [[TMP83]], [[BIN_RDX10]]
+; CHECK-NEXT:    [[TMP85:%.*]] = call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> [[BIN_RDX11]])
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 4096, 4096
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[LOOP_EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 4096, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[TMP85]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LATCH:%.*]] ]
+; CHECK-NEXT:    [[ACCUM:%.*]] = phi i32 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[ACCUM_NEXT:%.*]], [[LATCH]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[TEST_ADDR:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[IV]]
+; CHECK-NEXT:    [[EARLYCND:%.*]] = load i1, i1* [[TEST_ADDR]], align 1
+; CHECK-NEXT:    br i1 [[EARLYCND]], label [[PRED:%.*]], label [[LATCH]]
+; CHECK:       pred:
+; CHECK-NEXT:    [[ADDR:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[IV]]
+; CHECK-NEXT:    [[VAL:%.*]] = load i32, i32* [[ADDR]], align 4
+; CHECK-NEXT:    br label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    [[VAL_PHI:%.*]] = phi i32 [ 0, [[LOOP]] ], [ [[VAL]], [[PRED]] ]
+; CHECK-NEXT:    [[ACCUM_NEXT]] = add i32 [[ACCUM]], [[VAL_PHI]]
+; CHECK-NEXT:    [[EXIT:%.*]] = icmp ugt i64 [[IV]], 4094
+; CHECK-NEXT:    br i1 [[EXIT]], label [[LOOP_EXIT]], label [[LOOP]], [[LOOP27:!llvm.loop !.*]]
+; CHECK:       loop_exit:
+; CHECK-NEXT:    [[ACCUM_NEXT_LCSSA:%.*]] = phi i32 [ [[ACCUM_NEXT]], [[LATCH]] ], [ [[TMP85]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i32 [[ACCUM_NEXT_LCSSA]]
+;
+entry:
+  %allocation = call nonnull i8* @my_array_alloc(i32 4096, i32 4)
+  %base = bitcast i8* %allocation to i32*
+  call void @init(i32* %base)
+  br label %loop
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %latch ]
+  %accum = phi i32 [ 0, %entry ], [ %accum.next, %latch ]
+  %iv.next = add i64 %iv, 1
+  %test_addr = getelementptr inbounds i1, i1* %test_base, i64 %iv
+  %earlycnd = load i1, i1* %test_addr
+  br i1 %earlycnd, label %pred, label %latch
+pred:
+  %addr = getelementptr inbounds i32, i32* %base, i64 %iv
+  %val = load i32, i32* %addr
+  br label %latch
+latch:
+  %val.phi = phi i32 [0, %loop], [%val, %pred]
+  %accum.next = add i32 %accum, %val.phi
+  %exit = icmp ugt i64 %iv, 4094
+  br i1 %exit, label %loop_exit, label %loop
+
+loop_exit:
+  ret i32 %accum.next
+}
+
+declare void @my_free(i8*)
+
+; For the point in time variant of deref(N) semantics, show a negative
+; example where hoisting without explicit predication might introduce a
+; dynamic use after free.  (e.g. allzero is true when all elements of the
+; test vector are false and thus base is never accessed.)
+define i32 @test_allocsize_cond_deref(i1 %allzero, i1* %test_base) {
+; CHECK-LABEL: @test_allocsize_cond_deref(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ALLOCATION:%.*]] = call nonnull i8* @my_alloc(i32 16384)
+; CHECK-NEXT:    [[BASE:%.*]] = bitcast i8* [[ALLOCATION]] to i32*
+; CHECK-NEXT:    call void @init(i32* [[BASE]])
+; CHECK-NEXT:    br i1 [[ALLZERO:%.*]], label [[FREEIT:%.*]], label [[PREHEADER:%.*]]
+; CHECK:       freeit:
+; CHECK-NEXT:    call void @my_free(i8* [[ALLOCATION]])
+; CHECK-NEXT:    br label [[PREHEADER]]
+; CHECK:       preheader:
+; 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 i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP80:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI1:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP81:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI2:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP82:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_PHI3:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP83:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = add i64 [[INDEX]], 2
+; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[INDEX]], 3
+; CHECK-NEXT:    [[TMP4:%.*]] = add i64 [[INDEX]], 4
+; CHECK-NEXT:    [[TMP5:%.*]] = add i64 [[INDEX]], 5
+; CHECK-NEXT:    [[TMP6:%.*]] = add i64 [[INDEX]], 6
+; CHECK-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], 7
+; CHECK-NEXT:    [[TMP8:%.*]] = add i64 [[INDEX]], 8
+; CHECK-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], 9
+; CHECK-NEXT:    [[TMP10:%.*]] = add i64 [[INDEX]], 10
+; CHECK-NEXT:    [[TMP11:%.*]] = add i64 [[INDEX]], 11
+; CHECK-NEXT:    [[TMP12:%.*]] = add i64 [[INDEX]], 12
+; CHECK-NEXT:    [[TMP13:%.*]] = add i64 [[INDEX]], 13
+; CHECK-NEXT:    [[TMP14:%.*]] = add i64 [[INDEX]], 14
+; CHECK-NEXT:    [[TMP15:%.*]] = add i64 [[INDEX]], 15
+; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE:%.*]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP17:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP18:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP19:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP3]]
+; CHECK-NEXT:    [[TMP20:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP4]]
+; CHECK-NEXT:    [[TMP21:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP5]]
+; CHECK-NEXT:    [[TMP22:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP6]]
+; CHECK-NEXT:    [[TMP23:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP7]]
+; CHECK-NEXT:    [[TMP24:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP8]]
+; CHECK-NEXT:    [[TMP25:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP9]]
+; CHECK-NEXT:    [[TMP26:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP10]]
+; CHECK-NEXT:    [[TMP27:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP11]]
+; CHECK-NEXT:    [[TMP28:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP12]]
+; CHECK-NEXT:    [[TMP29:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP13]]
+; CHECK-NEXT:    [[TMP30:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP14]]
+; CHECK-NEXT:    [[TMP31:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[TMP15]]
+; CHECK-NEXT:    [[TMP32:%.*]] = load i1, i1* [[TMP16]], align 1
+; CHECK-NEXT:    [[TMP33:%.*]] = load i1, i1* [[TMP17]], align 1
+; CHECK-NEXT:    [[TMP34:%.*]] = load i1, i1* [[TMP18]], align 1
+; CHECK-NEXT:    [[TMP35:%.*]] = load i1, i1* [[TMP19]], align 1
+; CHECK-NEXT:    [[TMP36:%.*]] = insertelement <4 x i1> undef, i1 [[TMP32]], i32 0
+; CHECK-NEXT:    [[TMP37:%.*]] = insertelement <4 x i1> [[TMP36]], i1 [[TMP33]], i32 1
+; CHECK-NEXT:    [[TMP38:%.*]] = insertelement <4 x i1> [[TMP37]], i1 [[TMP34]], i32 2
+; CHECK-NEXT:    [[TMP39:%.*]] = insertelement <4 x i1> [[TMP38]], i1 [[TMP35]], i32 3
+; CHECK-NEXT:    [[TMP40:%.*]] = load i1, i1* [[TMP20]], align 1
+; CHECK-NEXT:    [[TMP41:%.*]] = load i1, i1* [[TMP21]], align 1
+; CHECK-NEXT:    [[TMP42:%.*]] = load i1, i1* [[TMP22]], align 1
+; CHECK-NEXT:    [[TMP43:%.*]] = load i1, i1* [[TMP23]], align 1
+; CHECK-NEXT:    [[TMP44:%.*]] = insertelement <4 x i1> undef, i1 [[TMP40]], i32 0
+; CHECK-NEXT:    [[TMP45:%.*]] = insertelement <4 x i1> [[TMP44]], i1 [[TMP41]], i32 1
+; CHECK-NEXT:    [[TMP46:%.*]] = insertelement <4 x i1> [[TMP45]], i1 [[TMP42]], i32 2
+; CHECK-NEXT:    [[TMP47:%.*]] = insertelement <4 x i1> [[TMP46]], i1 [[TMP43]], i32 3
+; CHECK-NEXT:    [[TMP48:%.*]] = load i1, i1* [[TMP24]], align 1
+; CHECK-NEXT:    [[TMP49:%.*]] = load i1, i1* [[TMP25]], align 1
+; CHECK-NEXT:    [[TMP50:%.*]] = load i1, i1* [[TMP26]], align 1
+; CHECK-NEXT:    [[TMP51:%.*]] = load i1, i1* [[TMP27]], align 1
+; CHECK-NEXT:    [[TMP52:%.*]] = insertelement <4 x i1> undef, i1 [[TMP48]], i32 0
+; CHECK-NEXT:    [[TMP53:%.*]] = insertelement <4 x i1> [[TMP52]], i1 [[TMP49]], i32 1
+; CHECK-NEXT:    [[TMP54:%.*]] = insertelement <4 x i1> [[TMP53]], i1 [[TMP50]], i32 2
+; CHECK-NEXT:    [[TMP55:%.*]] = insertelement <4 x i1> [[TMP54]], i1 [[TMP51]], i32 3
+; CHECK-NEXT:    [[TMP56:%.*]] = load i1, i1* [[TMP28]], align 1
+; CHECK-NEXT:    [[TMP57:%.*]] = load i1, i1* [[TMP29]], align 1
+; CHECK-NEXT:    [[TMP58:%.*]] = load i1, i1* [[TMP30]], align 1
+; CHECK-NEXT:    [[TMP59:%.*]] = load i1, i1* [[TMP31]], align 1
+; CHECK-NEXT:    [[TMP60:%.*]] = insertelement <4 x i1> undef, i1 [[TMP56]], i32 0
+; CHECK-NEXT:    [[TMP61:%.*]] = insertelement <4 x i1> [[TMP60]], i1 [[TMP57]], i32 1
+; CHECK-NEXT:    [[TMP62:%.*]] = insertelement <4 x i1> [[TMP61]], i1 [[TMP58]], i32 2
+; CHECK-NEXT:    [[TMP63:%.*]] = insertelement <4 x i1> [[TMP62]], i1 [[TMP59]], i32 3
+; CHECK-NEXT:    [[TMP64:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP65:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP4]]
+; CHECK-NEXT:    [[TMP66:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP8]]
+; CHECK-NEXT:    [[TMP67:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[TMP12]]
+; CHECK-NEXT:    [[TMP68:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 0
+; CHECK-NEXT:    [[TMP69:%.*]] = bitcast i32* [[TMP68]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_MASKED_LOAD:%.*]] = call <4 x i32> @llvm.masked.load.v4i32.p0v4i32(<4 x i32>* [[TMP69]], i32 4, <4 x i1> [[TMP39]], <4 x i32> undef)
+; CHECK-NEXT:    [[TMP70:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 4
+; CHECK-NEXT:    [[TMP71:%.*]] = bitcast i32* [[TMP70]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_MASKED_LOAD4:%.*]] = call <4 x i32> @llvm.masked.load.v4i32.p0v4i32(<4 x i32>* [[TMP71]], i32 4, <4 x i1> [[TMP47]], <4 x i32> undef)
+; CHECK-NEXT:    [[TMP72:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 8
+; CHECK-NEXT:    [[TMP73:%.*]] = bitcast i32* [[TMP72]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_MASKED_LOAD5:%.*]] = call <4 x i32> @llvm.masked.load.v4i32.p0v4i32(<4 x i32>* [[TMP73]], i32 4, <4 x i1> [[TMP55]], <4 x i32> undef)
+; CHECK-NEXT:    [[TMP74:%.*]] = getelementptr inbounds i32, i32* [[TMP64]], i32 12
+; CHECK-NEXT:    [[TMP75:%.*]] = bitcast i32* [[TMP74]] to <4 x i32>*
+; CHECK-NEXT:    [[WIDE_MASKED_LOAD6:%.*]] = call <4 x i32> @llvm.masked.load.v4i32.p0v4i32(<4 x i32>* [[TMP75]], i32 4, <4 x i1> [[TMP63]], <4 x i32> undef)
+; CHECK-NEXT:    [[TMP76:%.*]] = xor <4 x i1> [[TMP39]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP77:%.*]] = xor <4 x i1> [[TMP47]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP78:%.*]] = xor <4 x i1> [[TMP55]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[TMP79:%.*]] = xor <4 x i1> [[TMP63]], <i1 true, i1 true, i1 true, i1 true>
+; CHECK-NEXT:    [[PREDPHI:%.*]] = select <4 x i1> [[TMP39]], <4 x i32> [[WIDE_MASKED_LOAD]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI7:%.*]] = select <4 x i1> [[TMP47]], <4 x i32> [[WIDE_MASKED_LOAD4]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI8:%.*]] = select <4 x i1> [[TMP55]], <4 x i32> [[WIDE_MASKED_LOAD5]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[PREDPHI9:%.*]] = select <4 x i1> [[TMP63]], <4 x i32> [[WIDE_MASKED_LOAD6]], <4 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP80]] = add <4 x i32> [[VEC_PHI]], [[PREDPHI]]
+; CHECK-NEXT:    [[TMP81]] = add <4 x i32> [[VEC_PHI1]], [[PREDPHI7]]
+; CHECK-NEXT:    [[TMP82]] = add <4 x i32> [[VEC_PHI2]], [[PREDPHI8]]
+; CHECK-NEXT:    [[TMP83]] = add <4 x i32> [[VEC_PHI3]], [[PREDPHI9]]
+; CHECK-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 16
+; CHECK-NEXT:    [[TMP84:%.*]] = icmp eq i64 [[INDEX_NEXT]], 4096
+; CHECK-NEXT:    br i1 [[TMP84]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], [[LOOP28:!llvm.loop !.*]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[BIN_RDX:%.*]] = add <4 x i32> [[TMP81]], [[TMP80]]
+; CHECK-NEXT:    [[BIN_RDX10:%.*]] = add <4 x i32> [[TMP82]], [[BIN_RDX]]
+; CHECK-NEXT:    [[BIN_RDX11:%.*]] = add <4 x i32> [[TMP83]], [[BIN_RDX10]]
+; CHECK-NEXT:    [[TMP85:%.*]] = call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> [[BIN_RDX11]])
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 4096, 4096
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[LOOP_EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 4096, [[MIDDLE_BLOCK]] ], [ 0, [[PREHEADER]] ]
+; CHECK-NEXT:    [[BC_MERGE_RDX:%.*]] = phi i32 [ 0, [[PREHEADER]] ], [ [[TMP85]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LATCH:%.*]] ]
+; CHECK-NEXT:    [[ACCUM:%.*]] = phi i32 [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ], [ [[ACCUM_NEXT:%.*]], [[LATCH]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[TEST_ADDR:%.*]] = getelementptr inbounds i1, i1* [[TEST_BASE]], i64 [[IV]]
+; CHECK-NEXT:    [[EARLYCND:%.*]] = load i1, i1* [[TEST_ADDR]], align 1
+; CHECK-NEXT:    br i1 [[EARLYCND]], label [[PRED:%.*]], label [[LATCH]]
+; CHECK:       pred:
+; CHECK-NEXT:    [[ADDR:%.*]] = getelementptr inbounds i32, i32* [[BASE]], i64 [[IV]]
+; CHECK-NEXT:    [[VAL:%.*]] = load i32, i32* [[ADDR]], align 4
+; CHECK-NEXT:    br label [[LATCH]]
+; CHECK:       latch:
+; CHECK-NEXT:    [[VAL_PHI:%.*]] = phi i32 [ 0, [[LOOP]] ], [ [[VAL]], [[PRED]] ]
+; CHECK-NEXT:    [[ACCUM_NEXT]] = add i32 [[ACCUM]], [[VAL_PHI]]
+; CHECK-NEXT:    [[EXIT:%.*]] = icmp ugt i64 [[IV]], 4094
+; CHECK-NEXT:    br i1 [[EXIT]], label [[LOOP_EXIT]], label [[LOOP]], [[LOOP29:!llvm.loop !.*]]
+; CHECK:       loop_exit:
+; CHECK-NEXT:    [[ACCUM_NEXT_LCSSA:%.*]] = phi i32 [ [[ACCUM_NEXT]], [[LATCH]] ], [ [[TMP85]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i32 [[ACCUM_NEXT_LCSSA]]
+;
+entry:
+  %allocation = call nonnull i8* @my_alloc(i32 16384)
+  %base = bitcast i8* %allocation to i32*
+  call void @init(i32* %base)
+  br i1 %allzero, label %freeit, label %preheader
+freeit:
+  call void @my_free(i8* %allocation)
+  br label %preheader
+preheader:
+  br label %loop
+loop:
+  %iv = phi i64 [ 0, %preheader ], [ %iv.next, %latch ]
+  %accum = phi i32 [ 0, %preheader ], [ %accum.next, %latch ]
+  %iv.next = add i64 %iv, 1
+  %test_addr = getelementptr inbounds i1, i1* %test_base, i64 %iv
+  %earlycnd = load i1, i1* %test_addr
+  br i1 %earlycnd, label %pred, label %latch
+pred:
+  %addr = getelementptr inbounds i32, i32* %base, i64 %iv
+  %val = load i32, i32* %addr
+  br label %latch
+latch:
+  %val.phi = phi i32 [0, %loop], [%val, %pred]
+  %accum.next = add i32 %accum, %val.phi
+  %exit = icmp ugt i64 %iv, 4094
+  br i1 %exit, label %loop_exit, label %loop
+
+loop_exit:
+  ret i32 %accum.next
+}


        


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