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

tests_lit/assembler/arm32/vsub.ll

+; Show that we know how to translate vsub.
+
+; 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 @testVsubFloat(float %v1, float %v2) {
+; ASM-LABEL: testVsubFloat:
+; DIS-LABEL: 00000000 <testVsubFloat>:
+; IASM-LABEL: testVsubFloat:
+
+entry:
+; ASM-NEXT: .LtestVsubFloat$entry:
+; IASM-NEXT: .LtestVsubFloat$entry:
+
+  %res = fsub float %v1, %v2
+
+; ASM-NEXT:     vsub.f32        s0, s0, s1
+; DIS-NEXT:    0:       ee300a60
+; IASM-NEXT:    .byte 0x60
+; IASM-NEXT:    .byte 0xa
+; IASM-NEXT:    .byte 0x30
+; IASM-NEXT:    .byte 0xee
+
+  ret float %res
+}
+
+define internal double @testVsubDouble(double %v1, double %v2) {
+; ASM-LABEL: testVsubDouble:
+; DIS-LABEL: 00000010 <testVsubDouble>:
+; IASM-LABEL: testVsubDouble:
+
+entry:
+; ASM-NEXT: .LtestVsubDouble$entry:
+; IASM-NEXT: .LtestVsubDouble$entry:
+
+  %res = fsub double %v1, %v2
+
+; ASM-NEXT:     vsub.f64        d0, d0, d1
+; DIS-NEXT:   10:       ee300b41
+; IASM-NEXT:    .byte 0x41
+; IASM-NEXT:    .byte 0xb
+; IASM-NEXT:    .byte 0x30
+; IASM-NEXT:    .byte 0xee
+
+  ret double %res
+}