Fix PR7193: if sibling call address can take a register, make sure there are enough registers available by counting inreg arguments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105092 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index a5fd1d1..0fd87bd 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2427,6 +2427,24 @@
}
}
}
+
+ // If the tailcall address may be in a register, then make sure it's
+ // possible to register allocate for it. In 32-bit, the call address can
+ // only target EAX, EDX, or ECX since the tail call must be scheduled after
+ // callee-saved registers are restored. In 64-bit, it's RAX, RCX, RDX, RSI,
+ // RDI, R8, R9, R11.
+ if (!isa<GlobalAddressSDNode>(Callee) &&
+ !isa<ExternalSymbolSDNode>(Callee)) {
+ unsigned Limit = Subtarget->is64Bit() ? 8 : 3;
+ unsigned NumInRegs = 0;
+ for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
+ CCValAssign &VA = ArgLocs[i];
+ if (VA.isRegLoc()) {
+ if (++NumInRegs == Limit)
+ return false;
+ }
+ }
+ }
}
return true;