Add multi-source/dest VMOV to the integrated ARM assembler.

tests_lit/assembler/arm32/vmov-dbl.ll

+; Show that we can generate vmov for bitcasts between i64 and double.
+
+; REQUIRES: allow_dump
+
+; Compile using standalone assembler.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --args -Om1 \
+; RUN:   -allow-extern -reg-use r5,r10,d20 \
+; 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:   -allow-extern -reg-use r5,r10,d20 \
+; RUN:   | FileCheck %s --check-prefix=DIS
+
+; Compile using integrated assembler.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --args -Om1 \
+; RUN:   -allow-extern -reg-use r5,r10,d20 \
+; 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:   -allow-extern -reg-use r5,r10,d20 \
+; RUN:   | FileCheck %s --check-prefix=DIS
+
+define internal i64 @convertDoubleToI64(double %d) {
+; ASM-LABEL: convertDoubleToI64:
+; DIS-LABEL: {{.+}} <convertDoubleToI64>:
+
+  %v = bitcast double %d to i64
+
+; ASM:  vmov    r5, r10, d20
+; DIS:   {{.+}}:    ec5a5b34
+; IASM-NOT: vmov
+
+  ret i64 %v
+}
+
+define internal double @convertI64ToDouble(i64 %i) {
+; ASM-LABEL: convertI64ToDouble:
+; DIS-LABEL: {{.+}} <convertI64ToDouble>:
+
+  %v = bitcast i64 %i to double
+
+; ASM:  vmov    d20, r5, r10
+; DIS:   {{.+}}:    ec4a5b34
+; IASM-NOT: vmov
+
+  ; Note: This call is added to allow %v to be put into d20 (instead of
+  ; return register d0).
+  call void @ignore(double %v)
+
+  ret double %v
+}
+
+declare external void @ignore(double)