diff --git a/llvm/test/Transforms/InstCombine/pow-exp.ll b/llvm/test/Transforms/InstCombine/pow-exp.ll
index fb8d9170e90cb..9d91ad2402eb1 100644
--- a/llvm/test/Transforms/InstCombine/pow-exp.ll
+++ b/llvm/test/Transforms/InstCombine/pow-exp.ll
@@ -1,4 +1,7 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Do not autogenerate
+;       Assertions were previously autogenerated by utils/update_test_checks.py
+;       but some hand modifications were needed to account for rounding errors
+;       in constant folding that depend on the compiler's math library version.
 ; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 define float @powf_expf(float %x, float %y) {
@@ -212,18 +215,18 @@ declare void @use_f(float)
 
 define double @pow_ok_base(double %e) {
 ; CHECK-LABEL: @pow_ok_base(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0xBFE0776228967D13
+; Do not change 0xBFE0776{{.*}} to the exact constant, see PR42740
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0xBFE0776{{.*}}
 ; CHECK-NEXT:    [[EXP2:%.*]] = tail call nnan ninf afn double @exp2(double [[MUL]])
 ; CHECK-NEXT:    ret double [[EXP2]]
 ;
-; Do not change 0xBFE0776{{.*}} to the exact constant, see PR42740
   %call = tail call afn nnan ninf double @pow(double 0x3FE6666666666666, double %e)
   ret double %call
 }
 
 define double @pow_ok_base_fast(double %e) {
 ; CHECK-LABEL: @pow_ok_base_fast(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul fast double [[E:%.*]], 0xBFE0776228967D13
+; CHECK-NEXT:    [[MUL:%.*]] = fmul fast double [[E:%.*]], 0xBFE0776{{.*}}
 ; CHECK-NEXT:    [[EXP2:%.*]] = tail call fast double @exp2(double [[MUL]])
 ; CHECK-NEXT:    ret double [[EXP2]]
 ;
@@ -233,7 +236,7 @@ define double @pow_ok_base_fast(double %e) {
 
 define double @pow_ok_base2(double %e) {
 ; CHECK-LABEL: @pow_ok_base2(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x4010952C788751AC
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x4010952{{.*}}
 ; CHECK-NEXT:    [[EXP2:%.*]] = tail call nnan ninf afn double @exp2(double [[MUL]])
 ; CHECK-NEXT:    ret double [[EXP2]]
 ;
@@ -243,7 +246,7 @@ define double @pow_ok_base2(double %e) {
 
 define double @pow_ok_base3(double %e) {
 ; CHECK-LABEL: @pow_ok_base3(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x400AB0B5584886CD
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x400AB0B5{{.*}}
 ; CHECK-NEXT:    [[EXP2:%.*]] = tail call nnan ninf afn double @exp2(double [[MUL]])
 ; CHECK-NEXT:    ret double [[EXP2]]
 ;
@@ -253,7 +256,7 @@ define double @pow_ok_base3(double %e) {
 
 define double @pow_ok_ten_base(double %e) {
 ; CHECK-LABEL: @pow_ok_ten_base(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x400A934F0979A371
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x400A934F{{.*}}
 ; CHECK-NEXT:    [[EXP2:%.*]] = tail call nnan ninf afn double @exp2(double [[MUL]])
 ; CHECK-NEXT:    ret double [[EXP2]]
 ;
@@ -273,7 +276,7 @@ define double @pow_ok_denorm_base(double %e) {
 
 define float @powf_ok_base(float %e) {
 ; CHECK-LABEL: @powf_ok_base(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0xBFE0776240000000
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0xBFE07762{{.*}}
 ; CHECK-NEXT:    [[EXP2F:%.*]] = tail call nnan ninf afn float @exp2f(float [[MUL]])
 ; CHECK-NEXT:    ret float [[EXP2F]]
 ;
@@ -283,7 +286,7 @@ define float @powf_ok_base(float %e) {
 
 define float @powf_ok_base2(float %e) {
 ; CHECK-LABEL: @powf_ok_base2(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x4010952C80000000
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x4010952{{.*}}
 ; CHECK-NEXT:    [[EXP2F:%.*]] = tail call nnan ninf afn float @exp2f(float [[MUL]])
 ; CHECK-NEXT:    ret float [[EXP2F]]
 ;
@@ -293,7 +296,7 @@ define float @powf_ok_base2(float %e) {
 
 define float @powf_ok_base3(float %e) {
 ; CHECK-LABEL: @powf_ok_base3(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x400AB0B560000000
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x400AB0B5{{.*}}
 ; CHECK-NEXT:    [[EXP2F:%.*]] = tail call nnan ninf afn float @exp2f(float [[MUL]])
 ; CHECK-NEXT:    ret float [[EXP2F]]
 ;
@@ -303,7 +306,7 @@ define float @powf_ok_base3(float %e) {
 
 define float @powf_ok_ten_base(float %e) {
 ; CHECK-LABEL: @powf_ok_ten_base(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x400A934F00000000
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x400A934{{.*}}
 ; CHECK-NEXT:    [[EXP2F:%.*]] = tail call nnan ninf afn float @exp2f(float [[MUL]])
 ; CHECK-NEXT:    ret float [[EXP2F]]
 ;
@@ -370,7 +373,7 @@ define double @pow_negative_base(double %e) {
 
 define double @pow_multiuse(double %e) {
 ; CHECK-LABEL: @pow_multiuse(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x4002934F0979A371
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn double [[E:%.*]], 0x4002934{{.*}}
 ; CHECK-NEXT:    [[EXP2:%.*]] = tail call nnan ninf afn double @exp2(double [[MUL]])
 ; CHECK-NEXT:    tail call void @use_d(double [[EXP2]])
 ; CHECK-NEXT:    ret double [[EXP2]]
@@ -400,7 +403,7 @@ define double @pow_ok_base_no_nnan(double %e) {
 
 define double @pow_ok_base_no_ninf(double %e) {
 ; CHECK-LABEL: @pow_ok_base_no_ninf(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan afn double [[E:%.*]], 0xBFE0776228967D13
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan afn double [[E:%.*]], 0xBFE0776{{.*}}
 ; CHECK-NEXT:    [[EXP2:%.*]] = tail call nnan afn double @exp2(double [[MUL]])
 ; CHECK-NEXT:    ret double [[EXP2]]
 ;
@@ -455,7 +458,7 @@ define float @powf_negative_base(float %e) {
 
 define float @powf_multiuse(float %e) {
 ; CHECK-LABEL: @powf_multiuse(
-; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x4002934F00000000
+; CHECK-NEXT:    [[MUL:%.*]] = fmul nnan ninf afn float [[E:%.*]], 0x4002934{{.*}}
 ; CHECK-NEXT:    [[EXP2F:%.*]] = tail call nnan ninf afn float @exp2f(float [[MUL]])
 ; CHECK-NEXT:    tail call void @use_f(float [[EXP2F]])
 ; CHECK-NEXT:    ret float [[EXP2F]]