Reland "Propagating values from if clauses to its successors"

This reverts commit fa1034c563b44c4f557814c50e2678e14dcd1d13.

Reason for revert: Relanding after float/double fix. In short,
don't deal with floats/doubles since they bring a lot of edge cases e.g.

  if (f == 0.0f) {
    // f is not guaranteed to be 0.0f, e.g. it could be -0.0f.
  }

Bug: 240543764
Change-Id: I400bdab71dba0934e6f1740538fe6e6c0a7bf5fc

1 files changed, 11 insertions, 2 deletions

diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 6ac4e07ca7..4fbb033c2f 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -1477,6 +1477,10 @@ bool HInstructionList::FoundBefore(const HInstruction* instruction1,
   UNREACHABLE();
 }
 
+bool HInstruction::Dominates(HInstruction* other_instruction) const {
+  return other_instruction == this || StrictlyDominates(other_instruction);
+}
+
 bool HInstruction::StrictlyDominates(HInstruction* other_instruction) const {
   if (other_instruction == this) {
     // An instruction does not strictly dominate itself.
@@ -1536,14 +1540,19 @@ void HInstruction::ReplaceWith(HInstruction* other) {
   DCHECK(env_uses_.empty());
 }
 
-void HInstruction::ReplaceUsesDominatedBy(HInstruction* dominator, HInstruction* replacement) {
+void HInstruction::ReplaceUsesDominatedBy(HInstruction* dominator,
+                                          HInstruction* replacement,
+                                          bool strictly_dominated) {
   const HUseList<HInstruction*>& uses = GetUses();
   for (auto it = uses.begin(), end = uses.end(); it != end; /* ++it below */) {
     HInstruction* user = it->GetUser();
     size_t index = it->GetIndex();
     // Increment `it` now because `*it` may disappear thanks to user->ReplaceInput().
     ++it;
-    if (dominator->StrictlyDominates(user)) {
+    const bool dominated =
+        strictly_dominated ? dominator->StrictlyDominates(user) : dominator->Dominates(user);
+
+    if (dominated) {
       user->ReplaceInput(replacement, index);
     } else if (user->IsPhi() && !user->AsPhi()->IsCatchPhi()) {
       // If the input flows from a block dominated by `dominator`, we can replace it.