Add VMOV(immediate) instructions to the ARM assembler.

tests_lit/assembler/arm32/vmov-imm.ll

+; Test moving constants into VPF registers.
+
+; REQUIRES: allow_dump
+
+; Compile using standalone assembler.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --args -Om1 -reg-use=d21,s20 \
+; 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 -reg-use=d21,s20 \
+; RUN:   | FileCheck %s --check-prefix=DIS
+
+; Compile using integrated assembler.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --args -Om1 -reg-use=d21,s20 \
+; 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 -reg-use=d21,s20 \
+; RUN:   | FileCheck %s --check-prefix=DIS
+
+define internal void @testMoveDouble() {
+; ASM-LABEL: testMoveDouble:
+; DIS-LABEL: 00000000 <testMoveDouble>:
+
+entry:
+  %addr = inttoptr i32 0 to double*
+  store double 1.5, double* %addr, align 8

[Jim Stichnoth, 2016/01/26 17:37:36]

BTW, you can make this test even simpler by dropping the inttoptr instruction
and using:

  store double 1.5, double* undef, align 8

[Karl, 2016/01/26 19:12:48]

Surprisingly, this causes a pnacl-freeze error for the float case. For now,
leaving as is. Will look into why pnacl-freeze is failing.

+
+; ASM:  vmov.f64        d21, #1.500000e+00
+; DIS:    4:    eef75b08
+; IASM-NOT: vmov.f64
+
+  ret void
+}
+
+define internal void @testMoveFloat() {
+; ASM-LABEL: testMoveFloat:
+; DIS-LABEL: 00000010 <testMoveFloat>:
+
+entry:
+  %addr = inttoptr i32 0 to float*
+  store float 1.5, float* %addr, align 4
+
+; ASM:  vmov.f32        s20, #1.500000e+00
+; DIS:   18:    eeb7aa08
+; IASM-NOT: vmov.f32
+
+  ret void
+}