[ARM] Add support for the s,j,x,N,O inline asm constraints

A number of inline assembly constraints are currently supported by LLVM, but rejected as invalid by Clang:

Target independent constraints:

s: An integer constant, but allowing only relocatable values

ARM specific constraints:

j: An immediate integer between 0 and 65535 (valid for MOVW)
x: A 32, 64, or 128-bit floating-point/SIMD register: s0-s15, d0-d7, or q0-q3
N: An immediate integer between 0 and 31 (Thumb1 only)
O: An immediate integer which is a multiple of 4 between -508 and 508. (Thumb1 only)

This patch adds support to Clang for the missing constraints along with some checks to ensure that the constraints are used with the correct target and Thumb mode, and that immediates are within valid ranges (at least where possible). The constraints are already implemented in LLVM, but just a couple of minor corrections to checks (V8M Baseline includes MOVW so should work with 'j', 'N' and 'O' shouldn't be valid in Thumb2) so that Clang and LLVM are in line with each other and the documentation.

Differential Revision: https://reviews.llvm.org/D65863

Change-Id: I18076619e319bac35fbb60f590c069145c9d9a0a

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@371079 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index bbaa9431dec79b7fcf0fb6180e1bb2541b1e1552..8051c1083c883bb5edaf3676a195e7c1e8a18854 100644 (file)
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -15323,7 +15323,7 @@ void ARMTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       case 'j':
         // Constant suitable for movw, must be between 0 and
         // 65535.
-        if (Subtarget->hasV6T2Ops())
+        if (Subtarget->hasV6T2Ops() || (Subtarget->hasV8MBaselineOps()))
           if (CVal >= 0 && CVal <= 65535)
             break;
         return;
@@ -15431,7 +15431,7 @@ void ARMTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
         return;
 
       case 'N':
-        if (Subtarget->isThumb()) {  // FIXME thumb2
+        if (Subtarget->isThumb1Only()) {
           // This must be a constant between 0 and 31, for shift amounts.
           if (CVal >= 0 && CVal <= 31)
             break;
@@ -15439,7 +15439,7 @@ void ARMTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
         return;
 
       case 'O':
-        if (Subtarget->isThumb()) {  // FIXME thumb2
+        if (Subtarget->isThumb1Only()) {
           // This must be a multiple of 4 between -508 and 508, for
           // ADD/SUB sp = sp + immediate.
           if ((CVal >= -508 && CVal <= 508) && ((CVal & 3) == 0))