Revert "[mips] Fix the target specific instruction verifier"

This reverts commit r320974. The commit message lacked the Differential Revison: line.

llvm-svn: 320975

1 files changed, 15 insertions, 22 deletions

diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.cpp b/llvm/lib/Target/Mips/MipsInstrInfo.cpp
index 51ddc0d44c0..1bfd21c02db 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.cpp
@@ -538,19 +538,15 @@ bool MipsInstrInfo::findCommutedOpIndices(MachineInstr &MI, unsigned &SrcOpIdx1,
 }
 
 // ins, ext, dext*, dins have the following constraints:
-// X <= pos      <  Y
-// X <  size     <= Y
-// X <  pos+size <= Y
+// 0 <= pos      <  X
+// 0 <  size     <= X
+// 0 <  pos+size <= x
 //
-// dinsm and dinsu have the following constraints:
-// X <= pos      <  Y
-// X <= size     <= Y
-// X <  pos+size <= Y
-//
-// The callee of verifyInsExtInstruction however gives the bounds of
-// dins[um] like the other (d)ins (d)ext(um) instructions, so that this
-// function doesn't have to vary it's behaviour based on the instruction
-// being checked.
+// dinsm and dinsm have the following contraints:
+// 0 <= pos      <  X
+// 0 <= size     <= X
+// 0 <  pos+size <= x
+
 static bool verifyInsExtInstruction(const MachineInstr &MI, StringRef &ErrInfo,
                                     const int64_t PosLow, const int64_t PosHigh,
                                     const int64_t SizeLow,
@@ -599,18 +595,15 @@ bool MipsInstrInfo::verifyInstruction(const MachineInstr &MI,
     case Mips::DINS:
       return verifyInsExtInstruction(MI, ErrInfo, 0, 32, 0, 32, 0, 32);
     case Mips::DINSM:
-      // The ISA spec has a subtle difference difference between dinsm and dextm
-      // in that it says:
-      // 2 <= size <= 64 for 'dinsm' but 'dextm' has 32 < size <= 64.
-      // To make the bounds checks similar, the range 1 < size <= 64 is checked
-      // for 'dinsm'.
+      // The ISA spec has a subtle difference here in that it says:
+      //  2 <= size <= 64 for 'dinsm', so we change the bounds so that it
+      // is in line with the rest of instructions.
       return verifyInsExtInstruction(MI, ErrInfo, 0, 32, 1, 64, 32, 64);
     case Mips::DINSU:
-      // The ISA spec has a subtle difference between dinsu and dextu in that
-      // the size range of dinsu is specified as 1 <= size <= 32 whereas size
-      // for dextu is 0 < size <= 32. The range checked for dinsu here is
-      // 0 < size <= 32, which is equivalent and similar to dextu.
-      return verifyInsExtInstruction(MI, ErrInfo, 32, 64, 0, 32, 32, 64);
+      // The ISA spec has a subtle difference here in that it says:
+      //  2 <= size <= 64 for 'dinsm', so we change the bounds so that it
+      // is in line with the rest of instructions.
+      return verifyInsExtInstruction(MI, ErrInfo, 32, 64, 1, 32, 32, 64);
     case Mips::DEXT:
       return verifyInsExtInstruction(MI, ErrInfo, 0, 32, 0, 32, 0, 63);
     case Mips::DEXTM: