Quick compiler (arm64) Fix inline Math.round()

Math.round is detected and inlined for arm64.  However, the
arm64 backend incorrectly modified a source operand in place
during the round sequence.  Depending on how registers are
allocated, that modification could persist.  Changed to use a
temp register for the intermediate result.

Internal b/17411468

Change-Id: I7c636f985e193f8ff838768fde3b741e443bb1bb

3 files changed, 17 insertions, 3 deletions

diff --git a/compiler/dex/quick/arm64/fp_arm64.cc b/compiler/dex/quick/arm64/fp_arm64.cc
index d0b2636453..7268d707d9 100644
--- a/compiler/dex/quick/arm64/fp_arm64.cc
+++ b/compiler/dex/quick/arm64/fp_arm64.cc
@@ -424,11 +424,12 @@ bool Arm64Mir2Lir::GenInlinedRound(CallInfo* info, bool is_double) {
   RegLocation rl_dest = (is_double) ? InlineTargetWide(info) : InlineTarget(info);
   rl_src = (is_double) ? LoadValueWide(rl_src, kFPReg) : LoadValue(rl_src, kFPReg);
   RegLocation rl_result = EvalLoc(rl_dest, kCoreReg, true);
+  RegStorage r_imm_point5 = (is_double) ? AllocTempDouble() : AllocTempSingle();
   RegStorage r_tmp = (is_double) ? AllocTempDouble() : AllocTempSingle();
   // 0.5f and 0.5d are encoded in the same way.
-  NewLIR2(kA64Fmov2fI | wide, r_tmp.GetReg(), encoded_imm);
-  NewLIR3(kA64Fadd3fff | wide, rl_src.reg.GetReg(), rl_src.reg.GetReg(), r_tmp.GetReg());
-  NewLIR2((is_double) ? kA64Fcvtms2xS : kA64Fcvtms2ws, rl_result.reg.GetReg(), rl_src.reg.GetReg());
+  NewLIR2(kA64Fmov2fI | wide, r_imm_point5.GetReg(), encoded_imm);
+  NewLIR3(kA64Fadd3fff | wide, r_tmp.GetReg(), rl_src.reg.GetReg(), r_imm_point5.GetReg());
+  NewLIR2((is_double) ? kA64Fcvtms2xS : kA64Fcvtms2ws, rl_result.reg.GetReg(), r_tmp.GetReg());
   (is_double) ? StoreValueWide(rl_dest, rl_result) : StoreValue(rl_dest, rl_result);
   return true;
 }
diff --git a/test/083-compiler-regressions/expected.txt b/test/083-compiler-regressions/expected.txt
index f8d92cc221..e907fd1d58 100644
--- a/test/083-compiler-regressions/expected.txt
+++ b/test/083-compiler-regressions/expected.txt
@@ -1,3 +1,4 @@
+b17411468 passes
 b2296099 passes
 b2302318 passes
 b2487514 passes
diff --git a/test/083-compiler-regressions/src/Main.java b/test/083-compiler-regressions/src/Main.java
index c089c527ab..8d7bf01192 100644
--- a/test/083-compiler-regressions/src/Main.java
+++ b/test/083-compiler-regressions/src/Main.java
@@ -30,6 +30,7 @@ public class Main {
     }
 
     public static void main(String args[]) throws Exception {
+        b17411468();
         b2296099Test();
         b2302318Test();
         b2487514Test();
@@ -61,6 +62,17 @@ public class Main {
         minDoubleWith3ConstsTest();
     }
 
+    public static void b17411468() {
+      // b/17411468 - inline Math.round failure.
+      double d1 = 1.0;
+      double d2 = Math.round(d1);
+      if (d1 == d2) {
+        System.out.println("b17411468 passes");
+      } else {
+        System.out.println("b17411468 fails: Math.round(" + d1 + ") returned " + d2);
+      }
+    }
+
     public static double minDouble(double a, double b, double c) {
         return Math.min(Math.min(a, b), c);
     }