fixup magic constant making code.  tested by thousands of random divisions.... by 10000.  ok, so random divisors would be good too, but this at least fixes some things

llvm-svn: 21140

llvm-svn: 21139

(X-Y)-X --> -Y
A + (B - A) --> B
(B - A) + A --> B

llvm-svn: 21138

llvm-svn: 21137

This occurs several dozen times in specint2k, particularly in crafty and gcc
apparently.

llvm-svn: 21136

llvm-svn: 21135

llvm-svn: 21134

llvm-svn: 21133

llvm-svn: 21132

llvm-svn: 21131

llvm-svn: 21130

llvm-svn: 21129

elements auto of the autoCSE maps.

llvm-svn: 21128

other things.

llvm-svn: 21127

llvm-svn: 21126

llvm-svn: 21125

llvm-svn: 21124

but should not require it.

llvm-svn: 21123

like PowerPC to codegen long shifts in many fewer instructions.

llvm-svn: 21122

llvm-svn: 21121

properly sign extending the top of the result of a 64-bit shift right by
a constant > 32.

llvm-svn: 21120

llvm-svn: 21119

llvm-svn: 21117

llvm-svn: 21116

llvm-svn: 21115

thanks sampo!!

llvm-svn: 21113

llvm-svn: 21112

quotient, not the remainder.  Also, make sure to remove the old div operand
from the ExprMap and let SelectExpr insert the new one.

llvm-svn: 21111

care of this ourselves

llvm-svn: 21110

llvm-svn: 21109

llvm-svn: 21108

llvm-svn: 21107

llvm-svn: 21106

time.

llvm-svn: 21105

Have LegalizeDAG handle SREM and UREM for us
Codegen SDIV and UDIV by constant as a multiply by magic constant instead
of integer divide, which is very slow.

llvm-svn: 21104

llvm-svn: 21103

multiply.

llvm-svn: 21102

llvm-svn: 21101

readable slwi or srwi (shift left/right word immediate).

llvm-svn: 21099

llvm-svn: 21098