Index: llvm/lib/Transforms/Utils/SimplifyCFG.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -4531,15 +4531,36 @@
         Changed = true;
       } else {
         assert(BI->isConditional() && "Can't get here with an uncond branch.");
-        Value* Cond = BI->getCondition();
+        Value *Cond = BI->getCondition();
         assert(BI->getSuccessor(0) != BI->getSuccessor(1) &&
                "The destinations are guaranteed to be different here.");
+
+        // We are eliminating at least one use of the condition by erasing the
+        // conditional branch. If there are other uses of the condition or its
+        // operands, preserve information for those uses by creating an assume.
+        auto shouldCreateAssume = [](Value *Cond) {
+          if (!Cond->hasOneUse())
+            return true;
+
+          CmpInst::Predicate Pred;
+          Value *X, *Y;
+          if (match(Cond, m_Cmp(Pred, m_Value(X), m_Value(Y)))) {
+            if (!isa<Constant>(X) && !X->hasOneUse())
+              return true;
+            if (!isa<Constant>(Y) && !Y->hasOneUse())
+              return true;
+          }
+          return false;
+        };
+
         if (BI->getSuccessor(0) == BB) {
-          Builder.CreateAssumption(Builder.CreateNot(Cond));
+          if (shouldCreateAssume(Cond))
+            Builder.CreateAssumption(Builder.CreateNot(Cond));
           Builder.CreateBr(BI->getSuccessor(1));
         } else {
           assert(BI->getSuccessor(1) == BB && "Incorrect CFG");
-          Builder.CreateAssumption(Cond);
+          if (shouldCreateAssume(Cond))
+            Builder.CreateAssumption(Cond);
           Builder.CreateBr(BI->getSuccessor(0));
         }
         EraseTerminatorAndDCECond(BI);
Index: llvm/test/Transforms/LoopVectorize/if-pred-stores.ll
===================================================================
--- llvm/test/Transforms/LoopVectorize/if-pred-stores.ll
+++ llvm/test/Transforms/LoopVectorize/if-pred-stores.ll
@@ -194,8 +194,6 @@
 define void @bug18724(i1 %cond) {
 ; UNROLL-LABEL: @bug18724(
 ; UNROLL-NEXT:  entry:
-; UNROLL-NEXT:    [[TMP0:%.*]] = xor i1 [[COND:%.*]], true
-; UNROLL-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; UNROLL-NEXT:    br label [[FOR_BODY14:%.*]]
 ; UNROLL:       for.body14:
 ; UNROLL-NEXT:    [[INDVARS_IV3:%.*]] = phi i64 [ [[INDVARS_IV_NEXT4:%.*]], [[FOR_INC23:%.*]] ], [ undef, [[ENTRY:%.*]] ]
@@ -210,9 +208,6 @@
 ; UNROLL:       for.inc23:
 ; UNROLL-NEXT:    [[INEWCHUNKS_2]] = phi i32 [ [[INC21]], [[IF_THEN18]] ], [ [[INEWCHUNKS_120]], [[FOR_BODY14]] ]
 ; UNROLL-NEXT:    [[INDVARS_IV_NEXT4]] = add nsw i64 [[INDVARS_IV3]], 1
-; UNROLL-NEXT:    [[TMP1:%.*]] = trunc i64 [[INDVARS_IV3]] to i32
-; UNROLL-NEXT:    [[CMP13:%.*]] = icmp slt i32 [[TMP1]], 0
-; UNROLL-NEXT:    call void @llvm.assume(i1 [[CMP13]])
 ; UNROLL-NEXT:    br label [[FOR_BODY14]]
 ;
 ; UNROLL-NOSIMPLIFY-LABEL: @bug18724(
@@ -285,8 +280,6 @@
 ;
 ; VEC-LABEL: @bug18724(
 ; VEC-NEXT:  entry:
-; VEC-NEXT:    [[TMP0:%.*]] = xor i1 [[COND:%.*]], true
-; VEC-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; VEC-NEXT:    br label [[FOR_BODY14:%.*]]
 ; VEC:       for.body14:
 ; VEC-NEXT:    [[INDVARS_IV3:%.*]] = phi i64 [ [[INDVARS_IV_NEXT4:%.*]], [[FOR_INC23:%.*]] ], [ undef, [[ENTRY:%.*]] ]
@@ -301,9 +294,6 @@
 ; VEC:       for.inc23:
 ; VEC-NEXT:    [[INEWCHUNKS_2]] = phi i32 [ [[INC21]], [[IF_THEN18]] ], [ [[INEWCHUNKS_120]], [[FOR_BODY14]] ]
 ; VEC-NEXT:    [[INDVARS_IV_NEXT4]] = add nsw i64 [[INDVARS_IV3]], 1
-; VEC-NEXT:    [[TMP1:%.*]] = trunc i64 [[INDVARS_IV3]] to i32
-; VEC-NEXT:    [[CMP13:%.*]] = icmp slt i32 [[TMP1]], 0
-; VEC-NEXT:    call void @llvm.assume(i1 [[CMP13]])
 ; VEC-NEXT:    br label [[FOR_BODY14]]
 ;
 entry:
Index: llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
===================================================================
--- llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
+++ llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
@@ -4,8 +4,6 @@
 define void @test1(i1 %C, i1* %BP) {
 ; CHECK-LABEL: @test1(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    ret void
 ;
 entry:
@@ -64,8 +62,6 @@
 define void @test5(i1 %cond, i8* %ptr) {
 ; CHECK-LABEL: @test5(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[COND:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    store i8 2, i8* [[PTR:%.*]], align 8
 ; CHECK-NEXT:    ret void
 ;
@@ -109,8 +105,6 @@
 define void @test6(i1 %cond, i8* %ptr) {
 ; CHECK-LABEL: @test6(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[COND:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    store i8 2, i8* [[PTR:%.*]], align 8
 ; CHECK-NEXT:    ret void
 ;
@@ -149,8 +143,6 @@
 define i32 @test7(i1 %X) {
 ; CHECK-LABEL: @test7(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[X:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    ret i32 0
 ;
 entry:
@@ -168,8 +160,6 @@
 define void @test8(i1 %X, void ()* %Y) {
 ; CHECK-LABEL: @test8(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[X:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    call void [[Y:%.*]]()
 ; CHECK-NEXT:    ret void
 ;
@@ -211,9 +201,7 @@
 define void @test9(i1 %X, i8* %Y) {
 ; CHECK-LABEL: @test9(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[X:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
-; CHECK-NEXT:    [[TMP1:%.*]] = call i8* @fn_nonnull_noundef_arg(i8* [[Y:%.*]])
+; CHECK-NEXT:    [[TMP0:%.*]] = call i8* @fn_nonnull_noundef_arg(i8* [[Y:%.*]])
 ; CHECK-NEXT:    ret void
 ;
 entry:
@@ -267,9 +255,7 @@
 define void @test9_null_callsite(i1 %X, i8* %Y) {
 ; CHECK-LABEL: @test9_null_callsite(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[X:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
-; CHECK-NEXT:    [[TMP1:%.*]] = call i8* @fn_nonnull_arg(i8* noundef nonnull [[Y:%.*]])
+; CHECK-NEXT:    [[TMP0:%.*]] = call i8* @fn_nonnull_arg(i8* noundef nonnull [[Y:%.*]])
 ; CHECK-NEXT:    ret void
 ;
 entry:
@@ -308,10 +294,8 @@
 define void @test9_gep_zero(i1 %X, i8* %Y) {
 ; CHECK-LABEL: @test9_gep_zero(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[X:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i8, i8* [[Y:%.*]], i64 0
-; CHECK-NEXT:    [[TMP1:%.*]] = call i8* @fn_nonnull_noundef_arg(i8* [[GEP]])
+; CHECK-NEXT:    [[TMP0:%.*]] = call i8* @fn_nonnull_noundef_arg(i8* [[GEP]])
 ; CHECK-NEXT:    ret void
 ;
 entry:
@@ -330,11 +314,9 @@
 define void @test9_gep_bitcast(i1 %X, i32* %Y) {
 ; CHECK-LABEL: @test9_gep_bitcast(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[X:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i32, i32* [[Y:%.*]], i64 0
 ; CHECK-NEXT:    [[BC:%.*]] = bitcast i32* [[GEP]] to i8*
-; CHECK-NEXT:    [[TMP1:%.*]] = call i8* @fn_nonnull_noundef_arg(i8* [[BC]])
+; CHECK-NEXT:    [[TMP0:%.*]] = call i8* @fn_nonnull_noundef_arg(i8* [[BC]])
 ; CHECK-NEXT:    ret void
 ;
 entry:
Index: llvm/test/Transforms/SimplifyCFG/fold-branch-to-common-dest.ll
===================================================================
--- llvm/test/Transforms/SimplifyCFG/fold-branch-to-common-dest.ll
+++ llvm/test/Transforms/SimplifyCFG/fold-branch-to-common-dest.ll
@@ -847,9 +847,6 @@
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[FOR_COND1:%.*]]
 ; CHECK:       for.cond1:
-; CHECK-NEXT:    [[V:%.*]] = load i8, i8* @f.b, align 1
-; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i8 [[V]], 1
-; CHECK-NEXT:    call void @llvm.assume(i1 [[CMP]])
 ; CHECK-NEXT:    br label [[FOR_COND1]]
 ;
 entry:
Index: llvm/test/Transforms/SimplifyCFG/simplifyUnreachable-degenerate-conditional-branch-with-matching-destinations.ll
===================================================================
--- llvm/test/Transforms/SimplifyCFG/simplifyUnreachable-degenerate-conditional-branch-with-matching-destinations.ll
+++ llvm/test/Transforms/SimplifyCFG/simplifyUnreachable-degenerate-conditional-branch-with-matching-destinations.ll
@@ -8,9 +8,6 @@
 define void @widget() {
 ; CHECK-LABEL: @widget(
 ; CHECK-NEXT:  bb:
-; CHECK-NEXT:    [[I:%.*]] = load i16, i16* @global, align 1
-; CHECK-NEXT:    [[I13:%.*]] = icmp ne i16 [[I]], 0
-; CHECK-NEXT:    call void @llvm.assume(i1 [[I13]])
 ; CHECK-NEXT:    unreachable
 ;
 bb:
Index: llvm/test/Transforms/SimplifyCFG/switch-range-to-icmp.ll
===================================================================
--- llvm/test/Transforms/SimplifyCFG/switch-range-to-icmp.ll
+++ llvm/test/Transforms/SimplifyCFG/switch-range-to-icmp.ll
@@ -107,8 +107,6 @@
 define void @PR42737(i32* %a, i1 %c) {
 ; CHECK-LABEL: @PR42737(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    call void @llvm.assume(i1 [[TMP0]])
 ; CHECK-NEXT:    unreachable
 ;
 entry:
Index: llvm/test/Transforms/SimplifyCFG/unreachable_assume.ll
===================================================================
--- llvm/test/Transforms/SimplifyCFG/unreachable_assume.ll
+++ llvm/test/Transforms/SimplifyCFG/unreachable_assume.ll
@@ -1,6 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
+; We add an assume to preserve information about %p.
+
 define i32 @assume1(i32 %p) {
 ; CHECK-LABEL: @assume1(
 ; CHECK-NEXT:  entry:
@@ -22,6 +24,7 @@
   ret i32 %call
 }
 
+; We add an assume to preserve information about %p.
 
 define i32 @assume2(i32 %p) {
 ; CHECK-LABEL: @assume2(