1 files changed, 45 insertions, 41 deletions
diff --git a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
index 5782ae39cf0..5c329ffcae5 100644
--- a/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
+++ b/llvm/lib/Target/ARM/InstPrinter/ARMInstPrinter.cpp
@@ -807,52 +807,56 @@ void ARMInstPrinter::printMSRMaskOperand(const MCInst *MI, unsigned OpNum,
   const MCOperand &Op = MI->getOperand(OpNum);
   unsigned SpecRegRBit = Op.getImm() >> 4;
   unsigned Mask = Op.getImm() & 0xf;
+  uint64_t FeatureBits = getAvailableFeatures();
 
-  if (getAvailableFeatures() & ARM::FeatureMClass) {
+  if (FeatureBits & ARM::FeatureMClass) {
     unsigned SYSm = Op.getImm();
     unsigned Opcode = MI->getOpcode();
-    // For reads of the special registers ignore the "mask encoding" bits
-    // which are only for writes.
-    if (Opcode == ARM::t2MRS_M)
-      SYSm &= 0xff;
+
+    // For writes, handle extended mask bits if the DSP extension is present.
+    if (Opcode == ARM::t2MSR_M && (FeatureBits & ARM::FeatureDSPThumb2)) {
+      switch (SYSm) {
+      case 0x400: O << "apsr_g"; return;
+      case 0xc00: O << "apsr_nzcvqg"; return;
+      case 0x401: O << "iapsr_g"; return;
+      case 0xc01: O << "iapsr_nzcvqg"; return;
+      case 0x402: O << "eapsr_g"; return;
+      case 0xc02: O << "eapsr_nzcvqg"; return;
+      case 0x403: O << "xpsr_g"; return;
+      case 0xc03: O << "xpsr_nzcvqg"; return;
+      }
+    }
+
+    // Handle the basic 8-bit mask.
+    SYSm &= 0xff;
+
+    if (Opcode == ARM::t2MSR_M && (FeatureBits & ARM::HasV7Ops)) {
+      // ARMv7-M deprecates using MSR APSR without a _<bits> qualifier as an
+      // alias for MSR APSR_nzcvq.
+      switch (SYSm) {
+      case 0: O << "apsr_nzcvq"; return;
+      case 1: O << "iapsr_nzcvq"; return;
+      case 2: O << "eapsr_nzcvq"; return;
+      case 3: O << "xpsr_nzcvq"; return;
+      }
+    }
+
     switch (SYSm) {
     default: llvm_unreachable("Unexpected mask value!");
-    case     0:
-    case 0x800: O << "apsr"; return; // with _nzcvq bits is an alias for aspr
-    case 0x400: O << "apsr_g"; return;
-    case 0xc00: O << "apsr_nzcvqg"; return;
-    case     1:
-    case 0x801: O << "iapsr"; return; // with _nzcvq bits is an alias for iapsr
-    case 0x401: O << "iapsr_g"; return;
-    case 0xc01: O << "iapsr_nzcvqg"; return;
-    case     2:
-    case 0x802: O << "eapsr"; return; // with _nzcvq bits is an alias for eapsr
-    case 0x402: O << "eapsr_g"; return;
-    case 0xc02: O << "eapsr_nzcvqg"; return;
-    case     3:
-    case 0x803: O << "xpsr"; return; // with _nzcvq bits is an alias for xpsr
-    case 0x403: O << "xpsr_g"; return;
-    case 0xc03: O << "xpsr_nzcvqg"; return;
-    case     5:
-    case 0x805: O << "ipsr"; return;
-    case     6:
-    case 0x806: O << "epsr"; return;
-    case     7:
-    case 0x807: O << "iepsr"; return;
-    case     8:
-    case 0x808: O << "msp"; return;
-    case     9:
-    case 0x809: O << "psp"; return;
-    case  0x10:
-    case 0x810: O << "primask"; return;
-    case  0x11:
-    case 0x811: O << "basepri"; return;
-    case  0x12:
-    case 0x812: O << "basepri_max"; return;
-    case  0x13:
-    case 0x813: O << "faultmask"; return;
-    case  0x14:
-    case 0x814: O << "control"; return;
+    case  0: O << "apsr"; return;
+    case  1: O << "iapsr"; return;
+    case  2: O << "eapsr"; return;
+    case  3: O << "xpsr"; return;
+    case  5: O << "ipsr"; return;
+    case  6: O << "epsr"; return;
+    case  7: O << "iepsr"; return;
+    case  8: O << "msp"; return;
+    case  9: O << "psp"; return;
+    case 16: O << "primask"; return;
+    case 17: O << "basepri"; return;
+    case 18: O << "basepri_max"; return;
+    case 19: O << "faultmask"; return;
+    case 20: O << "control"; return;
     }
   }