PPC/s390: Ignore overflow/notoverflow for poisoning

R=joransiu@ca.ibm.com

Change-Id: Id88187906f82cc9956ffbc9c70e4a1fdd8b20b30
Reviewed-on: https://chromium-review.googlesource.com/1234974Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#56055}

src/compiler/ppc/code-generator-ppc.cc

@@ -2121,7 +2121,8 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
 void CodeGenerator::AssembleBranchPoisoning(FlagsCondition condition,
                                             Instruction* instr) {
   // TODO(John) Handle float comparisons (kUnordered[Not]Equal).
-  if (condition == kUnorderedEqual || condition == kUnorderedNotEqual) {
+  if (condition == kUnorderedEqual || condition == kUnorderedNotEqual ||
+      condition == kOverflow || condition == kNotOverflow) {
     return;
   }
 

src/compiler/s390/code-generator-s390.cc

@@ -2779,7 +2779,8 @@ void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
 void CodeGenerator::AssembleBranchPoisoning(FlagsCondition condition,
                                             Instruction* instr) {
   // TODO(John) Handle float comparisons (kUnordered[Not]Equal).
-  if (condition == kUnorderedEqual || condition == kUnorderedNotEqual) {
+  if (condition == kUnorderedEqual || condition == kUnorderedNotEqual ||
+      condition == kOverflow || condition == kNotOverflow) {
     return;
   }