Chris Lattner 70074e00a2 Implement simple promotion for cast elimination in instcombine. This is ... currently very limited, but can be extended in the future. For example, we now compile: uint %test30(uint %c1) { %c2 = cast uint %c1 to ubyte %c3 = xor ubyte %c2, 1 %c4 = cast ubyte %c3 to uint ret uint %c4 } to: _xor: movzbl 4(%esp), %eax xorl $1, %eax ret instead of: _xor: movb $1, %al xorb 4(%esp), %al movzbl %al, %eax ret More impressively, we now compile: struct B { unsigned bit : 1; }; void xor(struct B *b) { b->bit = b->bit ^ 1; } To (X86/PPC): _xor: movl 4(%esp), %eax xorl $-2147483648, (%eax) ret _xor: lwz r2, 0(r3) xoris r2, r2, 32768 stw r2, 0(r3) blr instead of (X86/PPC): _xor: movl 4(%esp), %eax movl (%eax), %ecx movl %ecx, %edx shrl $31, %edx # TRUNCATE movb %dl, %dl xorb $1, %dl movzbl %dl, %edx andl $2147483647, %ecx shll $31, %edx orl %ecx, %edx movl %edx, (%eax) ret _xor: lwz r2, 0(r3) srwi r4, r2, 31 xori r4, r4, 1 rlwimi r2, r4, 31, 0, 0 stw r2, 0(r3) blr This implements InstCombine/cast.ll:test30. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28273 91177308-0d34-0410-b5e6-96231b3b80d8		2006-05-13 02:06:03 +00:00
..
Hello	Remove trailing whitespace	2005-04-21 23:48:37 +00:00
Instrumentation	Add explicit #includes of <iostream>	2006-01-22 22:53:01 +00:00
IPO	Remove some dead variables.	2006-05-12 23:35:26 +00:00
Scalar	Implement simple promotion for cast elimination in instcombine. This is	2006-05-13 02:06:03 +00:00
Utils	Patch to make some xforms preserve each other. Patch contributed by	2006-05-09 04:13:41 +00:00
ExprTypeConvert.cpp	Remove dead stuff	2006-05-12 23:32:01 +00:00
LevelRaise.cpp	Make iostream #inclusion explicit	2006-01-22 23:32:06 +00:00
Makefile	DONT_BUILD_RELINKED is gone and implied by BUILD_ARCHIVE now	2005-10-24 02:26:13 +00:00
TransformInternals.cpp	Remove dead #include	2005-10-29 04:41:30 +00:00
TransformInternals.h	ConvertibleToGEP always returns 0, remove some old crufty code which	2005-07-26 16:38:28 +00:00