Add FABS intrinsic to the integrated ARM assembler.

tests_lit/assembler/arm32/vabs.ll

+; Show that we translate intrinsics for fabs on float and double.
+
+; REQUIRES: allow_dump
+
+; Compile using standalone assembler.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --args -Om1 \
+; RUN:   -reg-use s20,d22 \
+; RUN:   | FileCheck %s --check-prefix=ASM
+
+; Show bytes in assembled standalone code.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --assemble --disassemble \
+; RUN:   --args -Om1 \
+; RUN:   -reg-use s20,d22 \
+; RUN:   | FileCheck %s --check-prefix=DIS
+
+; Compile using integrated assembler.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --args -Om1 \
+; RUN:   -reg-use s20,d22 \
+; RUN:   | FileCheck %s --check-prefix=IASM
+
+; Show bytes in assembled integrated code.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --assemble --disassemble \
+; RUN:   --args -Om1 \
+; RUN:   -reg-use s20,d22 \
+; RUN:   | FileCheck %s --check-prefix=DIS
+
+declare float @llvm.fabs.f32(float)
+declare double @llvm.fabs.f64(double)
+
+define internal float @test_fabs_float(float %x) {
+; ASM-LABEL: test_fabs_float:
+; DIS-LABEL: 00000000 <test_fabs_float>:
+; IASM-LABEL: test_fabs_float:
+
+entry:
+  %r = call float @llvm.fabs.f32(float %x)
+
+; ASM:  vabs.f32        s20, s20
+; DIS:   10:    eeb0aaca
+; IASM-NOT: vabs.f32
+
+  ret float %r
+}
+
+define internal double @test_fabs_double(double %x) {
+; ASM-LABEL: test_fabs_double:
+; DIS-LABEL: 00000030 <test_fabs_double>:
+; IASM-LABEL: test_fabs_double:
+
+entry:
+  %r = call double @llvm.fabs.f64(double %x)
+
+; ASM:  vabs.f64        d22, d22
+; DIS:   3c:    eef06be6
+; IASM-NOT: vabs.64
+
+  ret double %r
+}