ok, this is something of a dirty hack, but it seems to work. (fixes e.g.
the SPASS miscompilation)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37750 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocBigBlock.cpp b/lib/CodeGen/RegAllocBigBlock.cpp
index 400d72a..c7f23f5 100644
--- a/lib/CodeGen/RegAllocBigBlock.cpp
+++ b/lib/CodeGen/RegAllocBigBlock.cpp
@@ -459,9 +459,23 @@
}
}
}
+
+ if(PhysReg == 0) { // ok, now we're desperate. We couldn't choose
+ // a register to spill by looking through the
+ // read timetable, so now we just spill the
+ // first allocatable register we find.
+
+ // for all physical regs in the RC,
+ for(TargetRegisterClass::iterator pReg = RC->begin();
+ pReg != RC->end(); ++pReg) {
+ // if we find a register we can spill
+ if(PhysRegsUsed[*pReg]>=-1)
+ PhysReg = *pReg; // choose it to be spilled
+ }
+ }
- assert(PhysReg && "couldn't grab a register from the table?");
- // TODO: assert that RC->contains(PhysReg) / handle aliased registers
+ assert(PhysReg && "couldn't choose a register to spill :( ");
+ // TODO: assert that RC->contains(PhysReg) / handle aliased registers?
// since we needed to look in the table we need to spill this register.
spillPhysReg(MBB, I, PhysReg);