Quick compiler: fix x86 special identity

The Quick compiler recognizes and specially handles a set of
small methods - including those that simply return one of their
arguments.  For x86, special identity was broken if the returned
argument was a double that was passed half in register and half
in memory.

internal b/17325447

Change-Id: I3a766977cdc0b4216d8ad65a9870c3250b32471e

3 files changed, 37 insertions, 0 deletions

diff --git a/compiler/dex/quick/mir_to_lir.cc b/compiler/dex/quick/mir_to_lir.cc
index c945f7f891..70ef991dee 100644
--- a/compiler/dex/quick/mir_to_lir.cc
+++ b/compiler/dex/quick/mir_to_lir.cc
@@ -201,6 +201,16 @@ void Mir2Lir::LoadArgDirect(int in_position, RegLocation rl_dest) {
     RegStorage reg_arg_low = GetArgMappingToPhysicalReg(in_position);
     RegStorage reg_arg_high = GetArgMappingToPhysicalReg(in_position + 1);
 
+    if (cu_->instruction_set == kX86) {
+      // Can't handle double split between reg & memory.  Flush reg half to memory.
+      if (rl_dest.reg.IsDouble() && (reg_arg_low.Valid() != reg_arg_high.Valid())) {
+        DCHECK(reg_arg_low.Valid());
+        DCHECK(!reg_arg_high.Valid());
+        Store32Disp(TargetPtrReg(kSp), offset, reg_arg_low);
+        reg_arg_low = RegStorage::InvalidReg();
+      }
+    }
+
     if (reg_arg_low.Valid() && reg_arg_high.Valid()) {
       OpRegCopyWide(rl_dest.reg, RegStorage::MakeRegPair(reg_arg_low, reg_arg_high));
     } else if (reg_arg_low.Valid() && !reg_arg_high.Valid()) {
diff --git a/test/083-compiler-regressions/expected.txt b/test/083-compiler-regressions/expected.txt
index 51bf8471c5..78c92fc51a 100644
--- a/test/083-compiler-regressions/expected.txt
+++ b/test/083-compiler-regressions/expected.txt
@@ -1,3 +1,4 @@
+b17325447 passes
 b17630605 passes
 b17411468 passes
 b2296099 passes
diff --git a/test/083-compiler-regressions/src/Main.java b/test/083-compiler-regressions/src/Main.java
index 9ad8ea7b1b..285c3608ca 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 {
+        b17325447();
         b17630605();
         b17411468();
         b2296099Test();
@@ -64,6 +65,31 @@ public class Main {
         minDoubleWith3ConstsTest();
     }
 
+    public static double b17325447_i1(int i1, double f) {
+      return f;
+    }
+
+    public static double b17325447_i2(int i1, int i2, double f) {
+      return f;
+    }
+
+    public static double b17325447_i3(int i1, int i2, int i3, double f) {
+      return f;
+    }
+
+    public static void b17325447() {
+      // b/17325447 - x86 handling of special identity method w/ double spanning reg/mem.
+      double d = 0.0;
+      d += b17325447_i1(123, 1.0);
+      d += b17325447_i2(123, 456, 2.0);
+      d += b17325447_i3(123, 456, 789, 3.0);
+      if (d == 6.0) {
+        System.out.println("b17325447 passes");
+      } else {
+        System.out.println("b17325447 fails: " + d);
+      }
+    }
+
     public static void b17630605() {
       // b/17630605 - failure to properly handle min long immediates.
       long a1 = 40455547223404749L;