[X86] Add relaxtion logic for SBB instructions.

Prior to this patch, we would wrongly stick to the variant with imm8 encoding
even when the relocation could not fit that size.

rdar://problem/23785506

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255583 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp b/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
index 4136943a1176bf12958370e6244326be11708531..133bd0e1772aa6971d1dae3407fdbe289a66d9d9 100644 (file)
--- a/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ b/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -220,6 +220,14 @@ static unsigned getRelaxedOpcodeArith(unsigned Op) {
   case X86::SUB64ri8: return X86::SUB64ri32;
   case X86::SUB64mi8: return X86::SUB64mi32;
 
+   // SBB
+  case X86::SBB16ri8: return X86::SBB16ri;
+  case X86::SBB16mi8: return X86::SBB16mi;
+  case X86::SBB32ri8: return X86::SBB32ri;
+  case X86::SBB32mi8: return X86::SBB32mi;
+  case X86::SBB64ri8: return X86::SBB64ri32;
+  case X86::SBB64mi8: return X86::SBB64mi32;
+
     // CMP
   case X86::CMP16ri8: return X86::CMP16ri;
   case X86::CMP16mi8: return X86::CMP16mi;

diff --git a/test/MC/ELF/relax-arith.s b/test/MC/ELF/relax-arith.s
index 0e0d0a52d79ca8493a346b7a3457b27f92344cd5..56b7c399c4414a34741cd323151bad2febb90cd0 100644 (file)
--- a/test/MC/ELF/relax-arith.s
+++ b/test/MC/ELF/relax-arith.s
@@ -139,3 +139,19 @@ bar:
         adcl $foo, bar
         adc  $foo, %rbx
         adcq $foo, bar
+
+// CHECK:      Disassembly of section sbb:
+// CHECK-NEXT: sbb:
+// CHECK-NEXT:   0: 66 81 db 00 00                       sbbw $0, %bx
+// CHECK-NEXT:   5: 66 81 1c 25 00 00 00 00 00 00        sbbw $0, 0
+// CHECK-NEXT:   f: 81 db 00 00 00 00                    sbbl $0, %ebx
+// CHECK-NEXT:  15: 81 1c 25 00 00 00 00 00 00 00 00     sbbl $0, 0
+// CHECK-NEXT:  20: 48 81 db 00 00 00 00                 sbbq $0, %rbx
+// CHECK-NEXT:  27: 48 81 1c 25 00 00 00 00 00 00 00 00  sbbq $0, 0
+        .section sbb,"x"
+        sbb  $foo, %bx
+        sbbw $foo, bar
+        sbb  $foo, %ebx
+        sbbl $foo, bar
+        sbb  $foo, %rbx
+        sbbq $foo, bar