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| author | Evan Cheng <evan.cheng@apple.com> | 2008-03-12 22:19:41 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2008-03-12 22:19:41 +0000 |
| commit | 8725a1177fdd441520736f8f4af0f9a65ba07818 (patch) | |
| tree | f59ad6c6c050756f176a0445e95508876d99d8b4 /test/CodeGen/X86/2008-03-10-RegAllocInfLoop.ll | |
| parent | 40d4e512f1a420a79f8d8fca7abc6dc16add6059 (diff) | |
| download | external_llvm-8725a1177fdd441520736f8f4af0f9a65ba07818.zip external_llvm-8725a1177fdd441520736f8f4af0f9a65ba07818.tar.gz external_llvm-8725a1177fdd441520736f8f4af0f9a65ba07818.tar.bz2 | |
Experimental scheduler change to schedule / coalesce the copies added for function livein's. Take 2008-03-10-RegAllocInfLoop.ll, the schedule looks like this after these copies are inserted:
entry: 0x12049d0, LLVM BB @0x1201fd0, ID#0:
Live Ins: %EAX %EDX %ECX
%reg1031<def> = MOVPC32r 0
%reg1032<def> = ADD32ri %reg1031, <es:_GLOBAL_OFFSET_TABLE_>, %EFLAGS<imp-def>
%reg1028<def> = MOV32rr %EAX
%reg1029<def> = MOV32rr %EDX
%reg1030<def> = MOV32rr %ECX
%reg1027<def> = MOV8rm %reg0, 1, %reg0, 0, Mem:LD(1,1) [0x1201910 + 0]
%reg1025<def> = MOV32rr %reg1029
%reg1026<def> = MOV32rr %reg1030
%reg1024<def> = MOV32rr %reg1028
The copies unnecessarily increase register pressure and it will end up requiring a physical register to be spilled.
With -schedule-livein-copies:
entry: 0x12049d0, LLVM BB @0x1201fa0, ID#0:
Live Ins: %EAX %EDX %ECX
%reg1031<def> = MOVPC32r 0
%reg1032<def> = ADD32ri %reg1031, <es:_GLOBAL_OFFSET_TABLE_>, %EFLAGS<imp-def>
%reg1024<def> = MOV32rr %EAX
%reg1025<def> = MOV32rr %EDX
%reg1026<def> = MOV32rr %ECX
%reg1027<def> = MOV8rm %reg0, 1, %reg0, 0, Mem:LD(1,1) [0x12018e0 + 0]
Much better!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48307 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/CodeGen/X86/2008-03-10-RegAllocInfLoop.ll')
| -rw-r--r-- | test/CodeGen/X86/2008-03-10-RegAllocInfLoop.ll | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/test/CodeGen/X86/2008-03-10-RegAllocInfLoop.ll b/test/CodeGen/X86/2008-03-10-RegAllocInfLoop.ll index b858592..1098988 100644 --- a/test/CodeGen/X86/2008-03-10-RegAllocInfLoop.ll +++ b/test/CodeGen/X86/2008-03-10-RegAllocInfLoop.ll @@ -1,4 +1,5 @@ ; RUN: llvm-as < %s | llc -mtriple=i386-pc-linux-gnu -relocation-model=pic -disable-fp-elim +; RUN: llvm-as < %s | llc -mtriple=i386-pc-linux-gnu -relocation-model=pic -disable-fp-elim -schedule-livein-copies | not grep {Number of register spills} ; PR2134 declare fastcc i8* @w_addchar(i8*, i32*, i32*, i8 signext ) nounwind |