Tweak ARM assembly parsing and printing of MSR instruction.

The system register spec should be case insensitive. The preferred form for
output with mask values of 4, 8, and 12 references APSR rather than CPSR.
Update and tidy up tests accordingly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135532 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 2 deletions

diff --git a/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp b/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
index c90fe66f26..4a178dc921 100644
--- a/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
+++ b/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
@@ -481,10 +481,23 @@ void ARMInstPrinter::printMSRMaskOperand(const MCInst *MI, unsigned OpNum,
   unsigned SpecRegRBit = Op.getImm() >> 4;
   unsigned Mask = Op.getImm() & 0xf;
 
+  // As special cases, CPSR_f, CPSR_s and CPSR_fs prefer printing as
+  // APSR_nzcvq, APSR_g and APSRnzcvqg, respectively.
+  if (!SpecRegRBit && (Mask == 8 || Mask == 4 || Mask == 12)) {
+    O << "APSR_";
+    switch (Mask) {
+    default: assert(0);
+    case 4:  O << "g"; return;
+    case 8:  O << "nzcvq"; return;
+    case 12: O << "nzcvqg"; return;
+    }
+    llvm_unreachable("Unexpected mask value!");
+  }
+
   if (SpecRegRBit)
-    O << "spsr";
+    O << "SPSR";
   else
-    O << "cpsr";
+    O << "CPSR";
 
   if (Mask) {
     O << '_';