add RBIT instruction to the ARM integrated assembler.

tests_lit/assembler/arm32/rbit.ll

-; Show that we know how to translate rev (used in bswap).
+; Show that we know how to translate add.

[Jim Stichnoth, 2015/12/17 19:31:16]

rbit

[Karl, 2015/12/18 15:41:25]

Done.

 
 ; 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
 
-declare i16 @llvm.bswap.i16(i16)
+declare i32 @llvm.cttz.i32(i32, i1)
 
-define internal i32 @testRev(i32 %a) {
-; ASM-LABEL:testRev:
-; DIS-LABEL:00000000 <testRev>:
-; IASM-LABEL:testRev:
+define internal i32 @testRbit(i32 %a) {
+; ASM-LABEL: testRbit:
+; DIS-LABEL: 00000000 <testRbit>:
+; IASM-LABEL: testRbit:
 
 entry:
-; ASM-NEXT:.LtestRev$entry:
-; IASM-NEXT:.LtestRev$entry:
+; ASM-NEXT: .LtestRbit$entry:
+; IASM-NEXT: .LtestRbit$entry:
 
-  %a.arg_trunc = trunc i32 %a to i16
-  %v = tail call i16 @llvm.bswap.i16(i16 %a.arg_trunc)
+  %x = call i32 @llvm.cttz.i32(i32 %a, i1 0)
 
-; ***** Example of rev instruction. *****
-; ASM-NEXT:     rev     r0, r0
-; DIS-NEXT:   0:        e6bf0f30
+; ASM-NEXT:     rbit    r0, r0
+; DIS-NEXT:    0:       e6ff0f30
 ; IASM-NEXT:    .byte 0x30
 ; IASM-NEXT:    .byte 0xf
-; IASM-NEXT:    .byte 0xbf
+; IASM-NEXT:    .byte 0xff
 ; IASM-NEXT:    .byte 0xe6
 
-; ASM-NEXT:     lsr     r0, r0, #16
-
-  %.ret_ext = zext i16 %v to i32
-  ret i32 %.ret_ext
+  ret i32 %x
 }