Add VSUB{S,D} instructions to the integrated ARM assembler.

tests_lit/assembler/arm32/vadd.ll

 ; Show that we know how to translate vadd.
 
 ; NOTE: We use -O2 to get rid of memory stores.
 
 ; REQUIRES: allow_dump
 
 ; Compile using standalone assembler.
 ; RUN: %p2i --filetype=asm -i %s --target=arm32 --args -O2 \
 ; RUN:   | FileCheck %s --check-prefix=ASM
 
 ; Show bytes in assembled standalone code.
 ; RUN: %p2i --filetype=asm -i %s --target=arm32 --assemble --disassemble \
 ; RUN:   --args -O2 | FileCheck %s --check-prefix=DIS
 
 ; Compile using integrated assembler.
 ; RUN: %p2i --filetype=iasm -i %s --target=arm32 --args -O2 \
 ; RUN:   | FileCheck %s --check-prefix=IASM
 
 ; Show bytes in assembled integrated code.
 ; RUN: %p2i --filetype=iasm -i %s --target=arm32 --assemble --disassemble \
 ; RUN:   --args -O2 | FileCheck %s --check-prefix=DIS
 
-define internal float @testVadd(float %v1, float %v2) {
-; ASM-LABEL: testVadd:
-; DIS-LABEL: 00000000 <testVadd>:
-; IASM-LABEL: testVadd:
+define internal float @testVaddFloat(float %v1, float %v2) {
+; ASM-LABEL: testVaddFloat:
+; DIS-LABEL: 00000000 <testVaddFloat>:
+; IASM-LABEL: testVaddFloat:
 
 entry:
-; ASM-NEXT: .LtestVadd$entry:
-; IASM-NEXT: .LtestVadd$entry:
+; ASM-NEXT: .LtestVaddFloat$entry:
+; IASM-NEXT: .LtestVaddFloat$entry:
 
   %res = fadd float %v1, %v2
 
 ; ASM-NEXT:     vadd.f32        s0, s0, s1
 ; DIS-NEXT:    0:       ee300a20
 ; IASM-NEXT:    .byte 0x20
 ; IASM-NEXT:    .byte 0xa
 ; IASM-NEXT:    .byte 0x30
 ; IASM-NEXT:    .byte 0xee
 
   ret float %res
 }
+
+define internal double @testVaddDouble(double %v1, double %v2) {
+; ASM-LABEL: testVaddDouble:
+; DIS-LABEL: 00000010 <testVaddDouble>:
+; IASM-LABEL: testVaddDouble:
+
+entry:
+; ASM-NEXT: .LtestVaddDouble$entry:
+; IASM-NEXT: .LtestVaddDouble$entry:
+
+  %res = fadd double %v1, %v2
+
+; ASM-NEXT:     vadd.f64        d0, d0, d1
+; DIS-NEXT:   10:       ee300b01
+; IASM-NEXT:    .byte 0x1
+; IASM-NEXT:    .byte 0xb
+; IASM-NEXT:    .byte 0x30
+; IASM-NEXT:    .byte 0xee
+
+  ret double %res
+}