[mips] do not use FastISel when -mxgot is present

The clang compiler by default uses FastISel when invoked with -O0, which
is also the default. In that case, passing of -mxgot does not get honored,
i.e. the code path that is to deal with large got is not taken.
Clang produces same output regardless of -mxgot being present or not.
This change checks whether -mxgot is passed as an option, and turns off
FastISel if it is.

Patch by Stefan Maksimovic.

Differential Revision: https://reviews.llvm.org/D33593

llvm-svn: 304906

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index 87778434299..ce7dd09f429 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -470,8 +470,9 @@ MipsTargetLowering::createFastISel(FunctionLoweringInfo &funcInfo,
                      !Subtarget.hasMips32r6() && !Subtarget.inMips16Mode() &&
                      !Subtarget.inMicroMipsMode();
 
-  // Disable if we don't generate PIC or the ABI isn't O32.
-  if (!TM.isPositionIndependent() || !TM.getABI().IsO32())
+  // Disable if either of the following is true:
+  // We do not generate PIC, the ABI is not O32, LargeGOT is being used.
+  if (!TM.isPositionIndependent() || !TM.getABI().IsO32() || LargeGOT)
     UseFastISel = false;
 
   return UseFastISel ? Mips::createFastISel(funcInfo, libInfo) : nullptr;