[X86][Asm] Allow negative immediate to appear before bracketed expres…

…sion

Currently, only non-negative immediate is allowed prior to a brac expression (memory reference).
MASM / GAS does not have any problem cope with the left side of the real line, so we should be able to as well.

llvm: D36229

Differential Revision: https://reviews.llvm.org/D36230

llvm-svn: 310529

clang/test/CodeGen/ms-inline-asm.c

@@ -484,13 +484,13 @@ void t37() {
   __asm mov eax, (4 + 4) * 16
 // CHECK: mov eax, $$128
   __asm mov eax, 4 + 8 * -16
-// CHECK: mov eax, $$4294967172
+// CHECK: mov eax, $$-124
   __asm mov eax, 4 + 16 / -8
 // CHECK: mov eax, $$2
   __asm mov eax, (16 + 16) / -8
-// CHECK: mov eax, $$4294967292
+// CHECK: mov eax, $$-4
   __asm mov eax, ~15
-// CHECK: mov eax, $$4294967280
+// CHECK: mov eax, $$-16
   __asm mov eax, 6 ^ 3
 // CHECK: mov eax, $$5
 // CHECK: "~{eax},~{dirflag},~{fpsr},~{flags}"()
@@ -655,6 +655,12 @@ void t45() {
   // CHECK: call void asm sideeffect inteldialect "mov dr0, eax\0A\09mov dr1, ebx\0A\09mov dr2, ebx\0A\09mov dr3, ecx\0A\09mov dr6, edx\0A\09mov dr7, ecx", "~{dr0},~{dr1},~{dr2},~{dr3},~{dr6},~{dr7},~{dirflag},~{fpsr},~{flags}"()
 }
 
+void t46() {
+  // CHECK-LABEL: define void @t46
+  __asm add eax, -128[eax]
+  // CHECK: call void asm sideeffect inteldialect "add eax, $$-128[eax]", "~{eax},~{flags},~{dirflag},~{fpsr},~{flags}"()
+}
+
 void dot_operator(){
 // CHECK-LABEL: define void @dot_operator
 	__asm { mov eax, 3[ebx]A.b}