Chris Lattner 5f2c7b1975 Teach the instruction selector how to transform 'array' GEP computations into X86 ... scaled indexes. This allows us to compile GEP's like this: int* %test([10 x { int, { int } }]* %X, int %Idx) { %Idx = cast int %Idx to long %X = getelementptr [10 x { int, { int } }]* %X, long 0, long %Idx, ubyte 1, ubyte 0 ret int* %X } Into a single address computation: test: mov %EAX, DWORD PTR [%ESP + 4] mov %ECX, DWORD PTR [%ESP + 8] lea %EAX, DWORD PTR [%EAX + 8*%ECX + 4] ret Before it generated: test: mov %EAX, DWORD PTR [%ESP + 4] mov %ECX, DWORD PTR [%ESP + 8] shl %ECX, 3 add %EAX, %ECX lea %EAX, DWORD PTR [%EAX + 4] ret This is useful for things like int/float/double arrays, as the indexing can be folded into the loads&stores, reducing register pressure and decreasing the pressure on the decode unit. With these changes, I expect our performance on 256.bzip2 and gzip to improve a lot. On bzip2 for example, we go from this: 10665 asm-printer - Number of machine instrs printed 40 ra-local - Number of loads/stores folded into instructions 1708 ra-local - Number of loads added 1532 ra-local - Number of stores added 1354 twoaddressinstruction - Number of instructions added 1354 twoaddressinstruction - Number of two-address instructions 2794 x86-peephole - Number of peephole optimization performed to this: 9873 asm-printer - Number of machine instrs printed 41 ra-local - Number of loads/stores folded into instructions 1710 ra-local - Number of loads added 1521 ra-local - Number of stores added 789 twoaddressinstruction - Number of instructions added 789 twoaddressinstruction - Number of two-address instructions 2142 x86-peephole - Number of peephole optimization performed ... and these types of instructions are often in tight loops. Linear scan is also helped, but not as much. It goes from: 8787 asm-printer - Number of machine instrs printed 2389 liveintervals - Number of identity moves eliminated after coalescing 2288 liveintervals - Number of interval joins performed 3522 liveintervals - Number of intervals after coalescing 5810 liveintervals - Number of original intervals 700 spiller - Number of loads added 487 spiller - Number of stores added 303 spiller - Number of register spills 1354 twoaddressinstruction - Number of instructions added 1354 twoaddressinstruction - Number of two-address instructions 363 x86-peephole - Number of peephole optimization performed to: 7982 asm-printer - Number of machine instrs printed 1759 liveintervals - Number of identity moves eliminated after coalescing 1658 liveintervals - Number of interval joins performed 3282 liveintervals - Number of intervals after coalescing 4940 liveintervals - Number of original intervals 635 spiller - Number of loads added 452 spiller - Number of stores added 288 spiller - Number of register spills 789 twoaddressinstruction - Number of instructions added 789 twoaddressinstruction - Number of two-address instructions 258 x86-peephole - Number of peephole optimization performed Though I'm not complaining about the drop in the number of intervals. :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11820 91177308-0d34-0410-b5e6-96231b3b80d8		2004-02-25 07:00:55 +00:00
..
CBackend	Fix some unexpected fallout from the config.h changes. Because the CBE no	2004-02-24 18:34:10 +00:00
PowerPC	Add back machine code deleter pass until we get a MachineCode pass	2004-02-15 00:03:15 +00:00
SparcV9	FunctionLiveVarInfo.h moved: include/llvm/CodeGen -> lib/Target/Sparc/LiveVar	2004-02-24 19:46:00 +00:00
X86	Teach the instruction selector how to transform 'array' GEP computations into X86	2004-02-25 07:00:55 +00:00
Makefile	CBackend now lives here	2004-02-13 23:29:20 +00:00
MRegisterInfo.cpp	Put all LLVM code into the llvm namespace, as per bug 109.	2003-11-11 22:41:34 +00:00
Target.td	Expose the "Other" value type to tablegen targets	2004-02-11 03:08:45 +00:00
TargetData.cpp	Adjust to the changed StructType interface. In particular, getElementTypes() is gone.	2004-02-09 04:37:31 +00:00
TargetInstrInfo.cpp	Make this assertion more self-explanatory.	2004-01-15 18:15:58 +00:00
TargetMachine.cpp	Clean up a lot of the code I added yesterday by exposing the IntrinsicLowering	2003-12-28 21:23:38 +00:00
TargetSchedInfo.cpp	Put all LLVM code into the llvm namespace, as per bug 109.	2003-11-11 22:41:34 +00:00