[X86] Mark pseudo instruction TEST8ri_NOEREX as hasSIdeEffects=0.

Also, add a case clause in X86InstrInfo::shouldScheduleAdjacent to enable
macro-fusion.

<rdar://problem/15680770>

llvm-svn: 212747

lib/Target/X86/X86InstrArithmetic.td

@@ -1278,8 +1278,10 @@ let isCompare = 1 in {
     def TEST64mi32 : BinOpMI_F<"test", Xi64, X86testpat, MRM0m, 0xF6>;
 
     // When testing the result of EXTRACT_SUBREG sub_8bit_hi, make sure the
-    // register class is constrained to GR8_NOREX.
-    let isPseudo = 1 in
+    // register class is constrained to GR8_NOREX. This pseudo is explicitly
+    // marked side-effect free, since it doesn't have an isel pattern like
+    // other test instructions. 
+    let isPseudo = 1, hasSideEffects = 0 in
     def TEST8ri_NOREX : I<0, Pseudo, (outs), (ins GR8_NOREX:$src, i8imm:$mask),
                           "", [], IIC_BIN_NONMEM>, Sched<[WriteALU]>;
   } // Defs = [EFLAGS]

lib/Target/X86/X86InstrInfo.cpp

@@ -5037,6 +5037,7 @@ bool X86InstrInfo::shouldScheduleAdjacent(MachineInstr* First,
   case X86::TEST16rm:
   case X86::TEST32rm:
   case X86::TEST64rm:
+  case X86::TEST8ri_NOREX:
   case X86::AND16i16:
   case X86::AND16ri:
   case X86::AND16ri8:

test/CodeGen/X86/testb-je-fusion.ll

@@ -0,0 +1,20 @@
+; RUN: llc < %s -march=x86-64 -mcpu=corei7-avx | FileCheck %s
+
+; testb should be scheduled right before je to enable macro-fusion.
+
+; CHECK: testb $2, %{{[abcd]}}h
+; CHECK-NEXT: je
+
+define i32 @check_flag(i32 %flags, ...) nounwind {
+entry:
+  %and = and i32 %flags, 512
+  %tobool = icmp eq i32 %and, 0
+  br i1 %tobool, label %if.end, label %if.then
+
+if.then:
+  br label %if.end
+
+if.end:
+  %hasflag = phi i32 [ 1, %if.then ], [ 0, %entry ]
+  ret i32 %hasflag
+}