[SubZero] Fix size of arguments on stack

src/IceTargetLoweringMIPS32.cpp

Index: src/IceTargetLoweringMIPS32.cpp
diff --git a/src/IceTargetLoweringMIPS32.cpp b/src/IceTargetLoweringMIPS32.cpp
index e97fc5a576a69ce2a05569d0e69c2245c9243eff..ae03f3e12a1694d75ea934a0087b90f9ad82a25b 100644
--- a/src/IceTargetLoweringMIPS32.cpp
+++ b/src/IceTargetLoweringMIPS32.cpp
@@ -225,18 +225,31 @@ uint32_t TargetMIPS32::getCallStackArgumentsSizeBytes(const InstCall *Call) {
   TargetMIPS32::CallingConv CC;
   RegNumT DummyReg;
   size_t OutArgsSizeBytes = 0;
+  Variable *Dest = Call->getDest();
+  bool PartialOnStack = false;
+  if (Dest && isVectorFloatingType(Dest->getType())) {

[Jim Stichnoth, 2016/11/25 14:58:02]

if (Dest != nullptr && ...)

[jaydeep.patil, 2016/11/28 03:08:36]

Done.

+    CC.discardReg(RegMIPS32::Reg_A0);
+    // Next vector is partially on stack
+    PartialOnStack = true;
+  }
   for (SizeT i = 0, NumArgs = Call->getNumArgs(); i < NumArgs; ++i) {
     Operand *Arg = legalizeUndef(Call->getArg(i));
     const Type Ty = Arg->getType();
     RegNumT RegNum;
     if (CC.argInReg(Ty, i, &RegNum)) {
+      // If PartialOnStack is true and if this is a vector type

[Jim Stichnoth, 2016/11/25 14:58:02]

Reflow comment to 80-col

[jaydeep.patil, 2016/11/28 03:08:36]

Done.

+      // then last two elements are on stack
+      if (PartialOnStack == true && isVectorType(Ty)) {

[Jim Stichnoth, 2016/11/25 14:58:02]

if (PartialOnStack && ...)

[jaydeep.patil, 2016/11/28 03:08:36]

Done.

+        OutArgsSizeBytes = applyStackAlignmentTy(OutArgsSizeBytes, IceType_i32);
+        OutArgsSizeBytes += typeWidthInBytesOnStack(IceType_i32) * 2;
+      }
       continue;
     }
-
     OutArgsSizeBytes = applyStackAlignmentTy(OutArgsSizeBytes, Ty);
     OutArgsSizeBytes += typeWidthInBytesOnStack(Ty);
   }
-
+  // Add size of argument save area
+  OutArgsSizeBytes += MIPS32_MAX_GPR_ARG * 4;

[Jim Stichnoth, 2016/11/25 14:58:02]

Instead of "4", can you use something more symbolic/self-documenting?  like
(INT32_BITS/CHAR_BITS), or
  constexpr int BytesPerStackArg = 4;

[jaydeep.patil, 2016/11/28 03:08:36]

Done.

   return applyStackAlignment(OutArgsSizeBytes);
 }