Fix conditional jump over jmp (X86/X86-64/ARM32)

Optimize the code generation for 'if' statements to jump to the
'false' block if the next block to be generated is the 'true' block.

Add an X86-64 test for this case.

Note that ARM64 & MIPS64 have not been updated.

Change-Id: Iebb1352feb9d3bd0142d8b0621a2e3069a708ea7
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/optimizing/code_generator_utils.h b/compiler/optimizing/code_generator_utils.h
index 59b495c2c9..628eee8885 100644
--- a/compiler/optimizing/code_generator_utils.h
+++ b/compiler/optimizing/code_generator_utils.h
@@ -21,10 +21,19 @@
 
 namespace art {
 
+class Label;
+class HCondition;
+
 // Computes the magic number and the shift needed in the div/rem by constant algorithm, as out
 // arguments `magic` and `shift`
 void CalculateMagicAndShiftForDivRem(int64_t divisor, bool is_long, int64_t* magic, int* shift);
 
+// Is it valid to reverse the condition? Uses the values supplied to
+// GenerateTestAndBranch() in instruction generators.
+bool CanReverseCondition(Label* always_true_target,
+                         Label* false_target,
+                         HCondition* condition);
+
 }  // namespace art
 
 #endif  // ART_COMPILER_OPTIMIZING_CODE_GENERATOR_UTILS_H_