Implement UXTB and UXTH in the ARM integerated assembler.

tests_lit/assembler/arm32/uxtb.ll

+; Test the UXTB and UXTH instructions.
+
+; 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 i32 @_Z7testAddhh(i32 %a, i32 %b) {
+; ASM-LABEL: _Z7testAddhh:
+; DIS-LABEL: 00000000 <_Z7testAddhh>:
+; IASM-LABEL: _Z7testAddhh:
+
+entry:
+
+; ASM-NEXT: .L_Z7testAddhh$entry:
+; IASM-NEXT: .L_Z7testAddhh$entry:
+
+  %a.arg_trunc = trunc i32 %a to i8
+  %conv = zext i8 %a.arg_trunc to i32
+
+; ASM-NEXT:     uxtb    r0, r0
+; DIS-NEXT:    0:       e6ef0070
+; IASM-NEXT:    .byte 0x70
+; IASM-NEXT:    .byte 0x0
+; IASM-NEXT:    .byte 0xef
+; IASM-NEXT:    .byte 0xe6
+
+  %b.arg_trunc = trunc i32 %b to i8
+  %conv1 = zext i8 %b.arg_trunc to i32
+
+; ASM-NEXT:     uxtb    r1, r1
+; DIS-NEXT:    4:       e6ef1071
+; IASM-NEXT:    .byte 0x71
+; IASM-NEXT:    .byte 0x10
+; IASM-NEXT:    .byte 0xef
+; IASM-NEXT:    .byte 0xe6
+
+  %add = add i32 %conv1, %conv
+
+; ASM-NEXT:     add     r1, r1, r0
+; DIS-NEXT:    8:       e0811000
+; IASM-NEXT:    .byte 0x0
+; IASM-NEXT:    .byte 0x10
+; IASM-NEXT:    .byte 0x81
+; IASM-NEXT:    .byte 0xe0
+
+  %conv2 = trunc i32 %add to i16
+  %conv2.ret_ext = zext i16 %conv2 to i32
+
+; ASM-NEXT:     uxth    r1, r1
+; DIS-NEXT:   c:        e6ff1071
+; IASM-NEXT:    .byte 0x71
+; IASM-NEXT:    .byte 0x10
+; IASM-NEXT:    .byte 0xff
+; IASM-NEXT:    .byte 0xe6
+
+  ret i32 %conv2.ret_ext
+
+; ASM-NEXT:     mov     r0, r1
+; DIS-NEXT:   10:       e1a00001
+; IASM-NEXT:    mov     r0, r1
+
+; ASM-NEXT:     bx      lr
+; DIS-NEXT:   14:       e12fff1e
+; IASM-NEXT:    .byte 0x1e
+; IASM-NEXT:    .byte 0xff
+; IASM-NEXT:    .byte 0x2f
+; IASM-NEXT:    .byte 0xe1
+
+}
+