Add ARM fconsts/fconstd aliases for vmov.f32/vmov.f64

This commit adds the pre-UAL aliases of fconsts and fconstd for
vmov.f32 and vmov.f64. They use an InstAlias rather than a
MnemonicAlias to properly support the predicate operand.

We need to support encoded 8-bit constants in order to implement the
pre-UAL fconsts/fconstd aliases for vmov.f32/vmov.f64, so this
commit also fixes parsing of encoded floating point constants used
in vmov.f32/vmov.f64 instructions. Now we can support assembly code
like this:

  fconsts s0, #0x70

which is equivalent to vmov.f32 s0, #1.0.

Most of the code was already in place to support this feature.
Previously the code was trying to accept encoded 8-bit float
constants for the vmov.f32/vmov.f64 instructions.  It looks like the
support for parsing encoded floats was lost in a refactoring in
commit r148556 and we did not have any tests in place to catch it.

The change in this commit is to keep the parsed value as a 32-bit
float instead of a 64-bit double because that is what the isFPImm()
function expects to find. There is no loss of precision by using a
32-bit float here because we are still limited to an 8-bit encoded
value in the end.

Additionally, we explicitly reject encoded 8-bit floats for
vmovf.32/64. This is the same as the current behavior, but we now do
it explicitly rather than accidently.

llvm-svn: 198697

3 files changed, 87 insertions, 0 deletions

diff --git a/llvm/test/MC/ARM/fconst.s b/llvm/test/MC/ARM/fconst.s
new file mode 100644
index 00000000000..e2c1b3918ff
--- /dev/null
+++ b/llvm/test/MC/ARM/fconst.s
@@ -0,0 +1,22 @@
+@ RUN: llvm-mc -mcpu=cortex-a8 -triple armv7-apple-darwin -show-encoding < %s | FileCheck %s
+
+@ fconstd/fconsts aliases
+        fconsts s4, #0x0
+        fconsts s4, #0x70
+        fconstd d3, #0x0
+        fconstd d3, #0x70
+
+        fconstsne s5, #0x1
+        fconstsgt s5, #0x20
+        fconstdlt d2, #0x3
+        fconstdge d2, #0x40
+
+@ CHECK: vmov.f32        s4, #2.000000e+00 @ encoding: [0x00,0x2a,0xb0,0xee]
+@ CHECK: vmov.f32        s4, #1.000000e+00 @ encoding: [0x00,0x2a,0xb7,0xee]
+@ CHECK: vmov.f64        d3, #2.000000e+00 @ encoding: [0x00,0x3b,0xb0,0xee]
+@ CHECK: vmov.f64        d3, #1.000000e+00 @ encoding: [0x00,0x3b,0xb7,0xee]
+
+@ CHECK: vmovne.f32      s5, #2.125000e+00 @ encoding: [0x01,0x2a,0xf0,0x1e]
+@ CHECK: vmovgt.f32      s5, #8.000000e+00 @ encoding: [0x00,0x2a,0xf2,0xce]
+@ CHECK: vmovlt.f64      d2, #2.375000e+00 @ encoding: [0x03,0x2b,0xb0,0xbe]
+@ CHECK: vmovge.f64      d2, #1.250000e-01 @ encoding: [0x00,0x2b,0xb4,0xae]
diff --git a/llvm/test/MC/ARM/fp-const-errors.s b/llvm/test/MC/ARM/fp-const-errors.s
new file mode 100644
index 00000000000..2a68ddbe727
--- /dev/null
+++ b/llvm/test/MC/ARM/fp-const-errors.s
@@ -0,0 +1,22 @@
+@ RUN: not llvm-mc -mcpu=cortex-a8 -triple armv7-none-linux-gnueabi < %s 2>&1 | FileCheck %s
+
+@ Test for floating point constants that are out of the 8-bit encoded value range
+vmov.f32 s2, #32.0
+@ CHECK: error: invalid operand for instruction
+
+vmov.f64 d2, #32.0
+@ CHECK: error: invalid operand for instruction
+
+@ Test that vmov.f instructions do not accept an 8-bit encoded float as an operand
+vmov.f32 s1, #0x70
+@ CHECK: error: invalid floating point immediate
+
+vmov.f64 d2, #0x70
+@ CHECK: error: invalid floating point immediate
+
+@ Test that fconst instructions do not accept a float constant as an operand
+fconsts s1, #1.0
+@ CHECK: error: invalid floating point immediate
+
+fconstd d2, #1.0
+@ CHECK: error: invalid floating point immediate
diff --git a/llvm/test/MC/ARM/simple-fp-encoding.s b/llvm/test/MC/ARM/simple-fp-encoding.s
index d840e9cd798..539dd2c4d97 100644
--- a/llvm/test/MC/ARM/simple-fp-encoding.s
+++ b/llvm/test/MC/ARM/simple-fp-encoding.s
@@ -395,3 +395,46 @@
 
 @ CHECK: vmov.i32	d4, #0x0        @ encoding: [0x10,0x40,0x80,0xf2]
 @ CHECK: vmov.i32	d4, #0x42000000 @ encoding: [0x12,0x46,0x84,0xf2]
+
+@ Test encoding of floating point constants for vmov functions
+@ vfp3
+         vmov.f32 s5, #1.0
+         vmov.f32 s5, #0.125
+         vmov.f32 s5, #-1.875
+         vmov.f32 s5, #-0.59375
+
+         vmov.f64 d6, #1.0
+         vmov.f64 d6, #0.125
+         vmov.f64 d6, #-1.875
+         vmov.f64 d6, #-0.59375
+
+@ neon
+         vmov.f32 d7, #1.0
+         vmov.f32 d7, #0.125
+         vmov.f32 d7, #-1.875
+         vmov.f32 d7, #-0.59375
+
+         vmov.f32 q8, #1.0
+         vmov.f32 q8, #0.125
+         vmov.f32 q8, #-1.875
+         vmov.f32 q8, #-0.59375
+
+@ CHECK: vmov.f32        s5, #1.000000e+00 @ encoding: [0x00,0x2a,0xf7,0xee]
+@ CHECK: vmov.f32        s5, #1.250000e-01 @ encoding: [0x00,0x2a,0xf4,0xee]
+@ CHECK: vmov.f32        s5, #-1.875000e+00 @ encoding: [0x0e,0x2a,0xff,0xee]
+@ CHECK: vmov.f32        s5, #-5.937500e-01 @ encoding: [0x03,0x2a,0xfe,0xee]
+
+@ CHECK: vmov.f64        d6, #1.000000e+00 @ encoding: [0x00,0x6b,0xb7,0xee]
+@ CHECK: vmov.f64        d6, #1.250000e-01 @ encoding: [0x00,0x6b,0xb4,0xee]
+@ CHECK: vmov.f64        d6, #-1.875000e+00 @ encoding: [0x0e,0x6b,0xbf,0xee]
+@ CHECK: vmov.f64        d6, #-5.937500e-01 @ encoding: [0x03,0x6b,0xbe,0xee]
+
+@ CHECK: vmov.f32        d7, #1.000000e+00 @ encoding: [0x10,0x7f,0x87,0xf2]
+@ CHECK: vmov.f32        d7, #1.250000e-01 @ encoding: [0x10,0x7f,0x84,0xf2]
+@ CHECK: vmov.f32        d7, #-1.875000e+00 @ encoding: [0x1e,0x7f,0x87,0xf3]
+@ CHECK: vmov.f32        d7, #-5.937500e-01 @ encoding: [0x13,0x7f,0x86,0xf3]
+
+@ CHECK: vmov.f32        q8, #1.000000e+00 @ encoding: [0x50,0x0f,0xc7,0xf2]
+@ CHECK: vmov.f32        q8, #1.250000e-01 @ encoding: [0x50,0x0f,0xc4,0xf2]
+@ CHECK: vmov.f32        q8, #-1.875000e+00 @ encoding: [0x5e,0x0f,0xc7,0xf3]
+@ CHECK: vmov.f32        q8, #-5.937500e-01 @ encoding: [0x53,0x0f,0xc6,0xf3]