Fix a subtle difference between running clang vs llc for mips16.

This regards how mips16 is viewed. It's not really a target type but
there has always been a target for it in the td files. It's more properly
-mcpu=mips32 -mattr=+mips16 . This is how clang treats it but we have
always had the -mcpu=mips16 which I probably should delete now but it will
require updating all the .ll test cases for mips16. In this case it changed
how we decide if we have a count bits instruction and whether instruction
lowering should then expand ctlz. Now that we have dual mode compilation,
-mattr=+mips16 really just indicates the inital processor mode that
we are compiling for. (It is also possible to have -mcpu=64 -mattr=+mips16
but as far as I know, nobody has even built such a processor, though there
is an architecture manual for this).

llvm-svn: 188586

llvm/lib/Target/Mips/MipsSubtarget.cpp

@@ -95,6 +95,9 @@ MipsSubtarget::MipsSubtarget(const std::string &TT, const std::string &CPU,
 
   // Set UseSmallSection.
   UseSmallSection = !IsLinux && (RM == Reloc::Static);
+  // set some subtarget specific features
+  if (inMips16Mode())
+    HasBitCount=false;
 }
 
 bool

llvm/test/CodeGen/Mips/ctlz.ll

@@ -0,0 +1,27 @@
+; RUN: llc -mtriple=mipsel-linux-gnu -march=mipsel -mcpu=mips32 -mattr=+mips16 -soft-float -mips16-hard-float -relocation-model=static < %s | FileCheck %s -check-prefix=static
+
+@x = global i32 28912, align 4
+@y = common global i32 0, align 4
+
+
+; Function Attrs: nounwind
+define i32 @main() #0 {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  %0 = load i32* @x, align 4
+  %1 = call i32 @llvm.ctlz.i32(i32 %0, i1 true)
+  store i32 %1, i32* @y, align 4
+  ret i32 0
+}
+
+; static: .end main
+
+; Function Attrs: nounwind readnone
+declare i32 @llvm.ctlz.i32(i32, i1) #1
+
+
+
+attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="true" }
+attributes #1 = { nounwind readnone }
+