[mips] Compute stack alignment on the fly.

llvm-svn: 193673
diff --git a/llvm/lib/Target/Mips/MipsSubtarget.cpp b/llvm/lib/Target/Mips/MipsSubtarget.cpp
index 07957ef..0a81072 100644
--- a/llvm/lib/Target/Mips/MipsSubtarget.cpp
+++ b/llvm/lib/Target/Mips/MipsSubtarget.cpp
@@ -72,7 +72,7 @@
   InMips16Mode(false), InMips16HardFloat(Mips16HardFloat),
   InMicroMipsMode(false), HasDSP(false), HasDSPR2(false),
   AllowMixed16_32(Mixed16_32 | Mips_Os16), Os16(Mips_Os16), HasMSA(false),
-  StackAlignment(8), RM(_RM), OverrideMode(NoOverride), TM(_TM)
+  RM(_RM), OverrideMode(NoOverride), TM(_TM)
 {
   std::string CPUName = CPU;
   if (CPUName.empty())