[ARM] Disallow PC, and optionally SP, in VMOVRH and VMOVHR.

Arm v8.1-M supports the VMOV instructions that move a half-precision
value to and from a GPR, but not if the GPR is SP or PC.

To fix this, I've changed those instructions to use the rGPR register
class instead of GPR. rGPR always excludes PC, and it excludes SP
except in the presence of the HasV8Ops target feature (i.e. Arm v8-A).
So the effect is that VMOV.F16 to and from PC is now illegal
everywhere, but VMOV.F16 to and from SP is illegal only on non-v8-A
cores (which I believe is all as it should be).

Reviewers: dmgreen, samparker, SjoerdMeijer, ostannard

Reviewed By: ostannard

Subscribers: ostannard, javed.absar, kristof.beyls, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60704

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362942 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMInstrVFP.td b/lib/Target/ARM/ARMInstrVFP.td
index 6f042d39a4c4e570f4cd60832dc105898ec6834b..6498024869abbbe9c06cadb4da94d006a218c30c 100644 (file)
--- a/lib/Target/ARM/ARMInstrVFP.td
+++ b/lib/Target/ARM/ARMInstrVFP.td
@@ -1246,9 +1246,9 @@ def VMOVSRR : AVConv5I<0b11000100, 0b1010,
 
 // Move H->R, clearing top 16 bits
 def VMOVRH : AVConv2I<0b11100001, 0b1001,
-                      (outs GPR:$Rt), (ins HPR:$Sn),
+                      (outs rGPR:$Rt), (ins HPR:$Sn),
                       IIC_fpMOVSI, "vmov", ".f16\t$Rt, $Sn",
-                      [(set GPR:$Rt, (arm_vmovrh HPR:$Sn))]>,
+                      [(set rGPR:$Rt, (arm_vmovrh HPR:$Sn))]>,
              Requires<[HasFPRegs16]>,
              Sched<[WriteFPMOV]> {
   // Instruction operands.
@@ -1268,9 +1268,9 @@ def VMOVRH : AVConv2I<0b11100001, 0b1001,
 
 // Move R->H, clearing top 16 bits
 def VMOVHR : AVConv4I<0b11100000, 0b1001,
-                      (outs HPR:$Sn), (ins GPR:$Rt),
+                      (outs HPR:$Sn), (ins rGPR:$Rt),
                       IIC_fpMOVIS, "vmov", ".f16\t$Sn, $Rt",
-                      [(set HPR:$Sn, (arm_vmovhr GPR:$Rt))]>,
+                      [(set HPR:$Sn, (arm_vmovhr rGPR:$Rt))]>,
              Requires<[HasFPRegs16]>,
              Sched<[WriteFPMOV]> {
   // Instruction operands.

diff --git a/test/MC/ARM/vmovhr.s b/test/MC/ARM/vmovhr.s
new file mode 100644 (file)
index 0000000..608400d
--- /dev/null
+++ b/test/MC/ARM/vmovhr.s
@@ -0,0 +1,24 @@
+// RUN: not llvm-mc -triple=thumbv8.2a-none-eabi -mattr=+fp-armv8,+fullfp16 -show-encoding < %s 2>%t \
+// RUN:   | FileCheck %s
+// RUN:     FileCheck --check-prefix=ERROR < %t %s
+
+# CHECK: vmov.f16 r0, s13 @ encoding: [0x16,0xee,0x90,0x09]
+vmov.f16 r0, s13
+
+# CHECK: vmov.f16 s21, r1 @ encoding: [0x0a,0xee,0x90,0x19]
+vmov.f16 s21, r1
+
+# CHECK: vmov.f16 s2, sp @ encoding: [0x01,0xee,0x10,0xd9]
+vmov.f16 s2, sp
+
+# ERROR: :[[@LINE+2]]:{{[0-9]+}}: error: invalid instruction
+# ERROR: operand must be a register in range [r0, r14]
+vmov.f16 s3, pc
+
+# CHECK: vmov.f16 sp, s5 @ encoding: [0x12,0xee,0x90,0xd9]
+vmov.f16 sp, s5
+
+# ERROR: :[[@LINE+2]]:{{[0-9]+}}: error: invalid instruction
+# ERROR: operand must be a register in range [r0, r14]
+vmov.f16 pc, s8
+