Optimizing: Fix `SimplifyIfs()` for FP bias mismatch.

Test: m test-art-host-test
Test: testrunner.py --host --optimizing --interpreter
Change-Id: I8fd0cfa02ed3242c84143a4a99a76a4fec95a4ee

2 files changed, 55 insertions, 1 deletions

diff --git a/compiler/optimizing/dead_code_elimination.cc b/compiler/optimizing/dead_code_elimination.cc
index c5ec0b93b2..b8cd39e77f 100644
--- a/compiler/optimizing/dead_code_elimination.cc
+++ b/compiler/optimizing/dead_code_elimination.cc
@@ -488,7 +488,8 @@ void HDeadCodeElimination::MaybeAddPhi(HBasicBlock* block) {
 
     if (block_cond->GetLeft() != dominator_cond->GetLeft() ||
         block_cond->GetRight() != dominator_cond->GetRight() ||
-        block_cond->GetOppositeCondition() != dominator_cond->GetCondition()) {
+        block_cond->GetOppositeCondition() != dominator_cond->GetCondition() ||
+        block_cond->GetBias() != dominator_cond->GetBias()) {
       return;
     }
   }
diff --git a/test/2255-checker-branch-redirection/src/Main.java b/test/2255-checker-branch-redirection/src/Main.java
index bfc6381942..a2c04ef6e0 100644
--- a/test/2255-checker-branch-redirection/src/Main.java
+++ b/test/2255-checker-branch-redirection/src/Main.java
@@ -32,6 +32,15 @@ public class Main {
         assertEquals(30, $noinline$testEliminateIfParameterOppositeCondition(20, 10, 20 < 10));
         assertEquals(40, $noinline$testEliminateIfParameterOppositeCondition_2(20, 40, 20 < 40));
         assertEquals(30, $noinline$testEliminateIfParameterOppositeCondition_2(20, 10, 20 < 10));
+
+        assertEquals(2, $noinline$testEliminateIfFp(20.0, 40.0));
+        assertEquals(3, $noinline$testEliminateIfFp(20.0, 10.0));
+        assertEquals(3, $noinline$testEliminateIfFp(20.0, Double.NaN));
+        assertEquals(3, $noinline$testEliminateIfFp(Double.NaN, 10.0));
+        assertEquals(3, $noinline$testDoNotEliminateIfOppositeCondFpWrongBias(20.0, 40.0));
+        assertEquals(2, $noinline$testDoNotEliminateIfOppositeCondFpWrongBias(20.0, 10.0));
+        assertEquals(3, $noinline$testDoNotEliminateIfOppositeCondFpWrongBias(20.0, Double.NaN));
+        assertEquals(3, $noinline$testDoNotEliminateIfOppositeCondFpWrongBias(Double.NaN, 10.0));
     }
 
     private static int $noinline$emptyMethod(int a) {
@@ -274,6 +283,50 @@ public class Main {
         return result;
     }
 
+    /// CHECK-START: int Main.$noinline$testEliminateIfFp(double, double) dead_code_elimination$after_gvn (before)
+    /// CHECK:     If
+    /// CHECK:     If
+
+    /// CHECK-START: int Main.$noinline$testEliminateIfFp(double, double) dead_code_elimination$after_gvn (after)
+    /// CHECK:     If
+    /// CHECK-NOT: If
+    private static int $noinline$testEliminateIfFp(double a, double b) {
+        int result = 0;
+        if (a < b) {
+            $noinline$emptyMethod(0);
+        } else {
+            $noinline$emptyMethod(1);
+        }
+        if (a < b) {
+            result += $noinline$emptyMethod(2);
+        } else {
+            result += $noinline$emptyMethod(3);
+        }
+        return result;
+    }
+
+    /// CHECK-START: int Main.$noinline$testDoNotEliminateIfOppositeCondFpWrongBias(double, double) dead_code_elimination$initial (before)
+    /// CHECK:     If
+    /// CHECK:     If
+
+    /// CHECK-START: int Main.$noinline$testDoNotEliminateIfOppositeCondFpWrongBias(double, double) dead_code_elimination$initial (after)
+    /// CHECK:     If
+    /// CHECK:     If
+    private static int $noinline$testDoNotEliminateIfOppositeCondFpWrongBias(double a, double b) {
+        int result = 0;
+        if (a < b) {
+            $noinline$emptyMethod(0);
+        } else {
+            $noinline$emptyMethod(1);
+        }
+        if (a >= b) {
+            result += $noinline$emptyMethod(2);
+        } else {
+            result += $noinline$emptyMethod(3);
+        }
+        return result;
+    }
+
     public static void assertEquals(int expected, int result) {
         if (expected != result) {
             throw new Error("Expected: " + expected + ", found: " + result);