From df42cf39abb248d09b1629783638fb960b7cc68c Mon Sep 17 00:00:00 2001 From: Chad Rosier Date: Tue, 11 Dec 2012 00:18:02 +0000 Subject: Fall back to the selection dag isel to select tail calls. This shouldn't affect codegen for -O0 compiles as tail call markers are not emitted in unoptimized compiles. Testing with the external/internal nightly test suite reveals no change in compile time performance. Testing with -O1, -O2 and -O3 with fast-isel enabled did not cause any compile-time or execution-time failures. All tests were performed on my x86 machine. I'll monitor our arm testers to ensure no regressions occur there. In an upcoming clang patch I will be marking the objc_autoreleaseReturnValue and objc_retainAutoreleaseReturnValue as tail calls unconditionally. While it's theoretically true that this is just an optimization, it's an optimization that we very much want to happen even at -O0, or else ARC applications become substantially harder to debug. Part of rdar://12553082 llvm-svn: 169796 --- llvm/lib/Target/ARM/ARMFastISel.cpp | 3 +++ 1 file changed, 3 insertions(+) (limited to 'llvm/lib/Target/ARM') diff --git a/llvm/lib/Target/ARM/ARMFastISel.cpp b/llvm/lib/Target/ARM/ARMFastISel.cpp index 21bb1476440..c3a5e6472ef 100644 --- a/llvm/lib/Target/ARM/ARMFastISel.cpp +++ b/llvm/lib/Target/ARM/ARMFastISel.cpp @@ -2284,6 +2284,9 @@ bool ARMFastISel::SelectCall(const Instruction *I, // Can't handle inline asm. if (isa(Callee)) return false; + // Allow SelectionDAG isel to handle tail calls. + if (CI->isTailCall()) return false; + // Check the calling convention. ImmutableCallSite CS(CI); CallingConv::ID CC = CS.getCallingConv(); -- cgit v1.2.3