Index: llvm/include/llvm/Transforms/Scalar/GVN.h
===================================================================
--- llvm/include/llvm/Transforms/Scalar/GVN.h
+++ llvm/include/llvm/Transforms/Scalar/GVN.h
@@ -73,6 +73,7 @@
   Optional<bool> AllowPRE = None;
   Optional<bool> AllowLoadPRE = None;
   Optional<bool> AllowLoadInLoopPRE = None;
+  Optional<bool> AllowLoadPRESplitBackedge = None;
   Optional<bool> AllowMemDep = None;
 
   GVNOptions() = default;
@@ -94,6 +95,12 @@
     return *this;
   }
 
+  /// Enables or disables PRE of loads in GVN.
+  GVNOptions &setLoadPRESplitBackedge(bool LoadPRESplitBackedge) {
+    AllowLoadPRESplitBackedge = LoadPRESplitBackedge;
+    return *this;
+  }
+
   /// Enables or disables use of MemDepAnalysis.
   GVNOptions &setMemDep(bool MemDep) {
     AllowMemDep = MemDep;
@@ -130,6 +137,7 @@
   bool isPREEnabled() const;
   bool isLoadPREEnabled() const;
   bool isLoadInLoopPREEnabled() const;
+  bool isLoadPRESplitBackedgeEnabled() const;
   bool isMemDepEnabled() const;
 
   /// This class holds the mapping between values and value numbers.  It is used
Index: llvm/lib/Passes/PassBuilder.cpp
===================================================================
--- llvm/lib/Passes/PassBuilder.cpp
+++ llvm/lib/Passes/PassBuilder.cpp
@@ -1917,6 +1917,8 @@
       Result.setPRE(Enable);
     } else if (ParamName == "load-pre") {
       Result.setLoadPRE(Enable);
+    } else if (ParamName == "split-backedge-load-pre") {
+      Result.setLoadPRESplitBackedge(Enable);
     } else if (ParamName == "memdep") {
       Result.setMemDep(Enable);
     } else {
Index: llvm/lib/Transforms/Scalar/GVN.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/GVN.cpp
+++ llvm/lib/Transforms/Scalar/GVN.cpp
@@ -110,6 +110,9 @@
 static cl::opt<bool> GVNEnableLoadPRE("enable-load-pre", cl::init(true));
 static cl::opt<bool> GVNEnableLoadInLoopPRE("enable-load-in-loop-pre",
                                             cl::init(true));
+static cl::opt<bool>
+GVNEnableSplitBackedgeInLoadPRE("enable-split-backedge-in-load-pre",
+                                cl::init(true));
 static cl::opt<bool> GVNEnableMemDep("enable-gvn-memdep", cl::init(true));
 
 static cl::opt<uint32_t> MaxNumDeps(
@@ -639,6 +642,11 @@
   return Options.AllowLoadInLoopPRE.getValueOr(GVNEnableLoadInLoopPRE);
 }
 
+bool GVN::isLoadPRESplitBackedgeEnabled() const {
+  return Options.AllowLoadPRESplitBackedge.getValueOr(
+      GVNEnableSplitBackedgeInLoadPRE);
+}
+
 bool GVN::isMemDepEnabled() const {
   return Options.AllowMemDep.getValueOr(GVNEnableMemDep);
 }
@@ -1222,6 +1230,16 @@
         return false;
       }
 
+      // Do not split backedge as it will break the canonical loop form.
+      if (!isLoadPRESplitBackedgeEnabled())
+        if (DT->dominates(LoadBB, Pred)) {
+          LLVM_DEBUG(
+              dbgs()
+              << "COULD NOT PRE LOAD BECAUSE OF A BACKEDGE CRITICAL EDGE '"
+              << Pred->getName() << "': " << *LI << '\n');
+          return false;
+        }
+
       CriticalEdgePred.push_back(Pred);
     } else {
       // Only add the predecessors that will not be split for now.
Index: llvm/test/Transforms/GVN/PRE/load-pre-split-backedge.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/GVN/PRE/load-pre-split-backedge.ll
@@ -0,0 +1,58 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -basic-aa -gvn -enable-split-backedge-in-load-pre=true < %s | FileCheck %s --check-prefix=ON
+; RUN: opt -S -basic-aa -gvn -enable-split-backedge-in-load-pre=false < %s | FileCheck %s --check-prefix=OFF
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
+target triple = "i386-apple-darwin11.0.0"
+
+define i32 @test(i1 %b, i1 %c, i32* noalias %p, i32* noalias %q) {
+; ON-LABEL: @test(
+; ON-NEXT:  entry:
+; ON-NEXT:    [[Y1:%.*]] = load i32, i32* [[P:%.*]], align 4
+; ON-NEXT:    call void @use(i32 [[Y1]])
+; ON-NEXT:    br label [[HEADER:%.*]]
+; ON:       header:
+; ON-NEXT:    [[Y:%.*]] = phi i32 [ [[Y_PRE:%.*]], [[SKIP_HEADER_CRIT_EDGE:%.*]] ], [ [[Y]], [[HEADER]] ], [ [[Y1]], [[ENTRY:%.*]] ]
+; ON-NEXT:    call void @use(i32 [[Y]])
+; ON-NEXT:    br i1 [[B:%.*]], label [[SKIP:%.*]], label [[HEADER]]
+; ON:       skip:
+; ON-NEXT:    call void @clobber(i32* [[P]], i32* [[Q:%.*]])
+; ON-NEXT:    br i1 [[C:%.*]], label [[SKIP_HEADER_CRIT_EDGE]], label [[EXIT:%.*]]
+; ON:       skip.header_crit_edge:
+; ON-NEXT:    [[Y_PRE]] = load i32, i32* [[P]], align 4
+; ON-NEXT:    br label [[HEADER]]
+; ON:       exit:
+; ON-NEXT:    ret i32 [[Y]]
+;
+; OFF-LABEL: @test(
+; OFF-NEXT:  entry:
+; OFF-NEXT:    [[Y1:%.*]] = load i32, i32* [[P:%.*]], align 4
+; OFF-NEXT:    call void @use(i32 [[Y1]])
+; OFF-NEXT:    br label [[HEADER:%.*]]
+; OFF:       header:
+; OFF-NEXT:    [[Y:%.*]] = load i32, i32* [[P]], align 4
+; OFF-NEXT:    call void @use(i32 [[Y]])
+; OFF-NEXT:    br i1 [[B:%.*]], label [[SKIP:%.*]], label [[HEADER]]
+; OFF:       skip:
+; OFF-NEXT:    call void @clobber(i32* [[P]], i32* [[Q:%.*]])
+; OFF-NEXT:    br i1 [[C:%.*]], label [[HEADER]], label [[EXIT:%.*]]
+; OFF:       exit:
+; OFF-NEXT:    ret i32 [[Y]]
+;
+entry:
+  %y1 = load i32, i32* %p
+  call void @use(i32 %y1)
+  br label %header
+header:
+  %y = load i32, i32* %p
+  call void @use(i32 %y)
+  br i1 %b, label %skip, label %header
+skip:
+  call void @clobber(i32* %p, i32* %q)
+  br i1 %c, label %header, label %exit
+exit:
+  ret i32 %y
+}
+
+declare void @use(i32) readonly
+declare void @clobber(i32* %p, i32* %q)