Chris Lattner 895c4ab564 Fold (x << c1)>> c2 into a single shift if the bits shifted out aren't used. ...

This compiles:
int baz(long long a) { return (short)(((int)(a >>24)) >> 9); }

into:
_baz:
        srwi r2, r3, 1
        extsh r3, r2
        blr

on PPC, instead of:
_baz:
        slwi r2, r3, 8
        srwi r2, r2, 9
        extsh r3, r2
        blr

GCC produces:
_baz:
        srwi r10,r4,24
        insrwi r10,r3,24,0
        srawi r9,r3,24
        srawi r3,r10,9
        extsh r3,r3
        blr

This implements CodeGen/PowerPC/shl_elim.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36221 91177308-0d34-0410-b5e6-96231b3b80d8

2007-04-17 21:14:16 +00:00

..

Analysis

Remove use of Instruction::getNext

2007-04-17 17:52:45 +00:00

Archive

…

AsmParser

Regenerate

2007-04-16 22:02:23 +00:00

Bytecode

Make long line fit in 80 cols.

2007-04-16 23:32:28 +00:00

CodeGen

Fold (x << c1)>> c2 into a single shift if the bits shifted out aren't used.

2007-04-17 21:14:16 +00:00

Debugger

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ExecutionEngine

eliminate use of Instruction::getPrev(). Patch by Gabor Greif in 2005.

2007-04-17 17:38:28 +00:00

Linker

Implement the "thread_local" keyword.

2007-04-12 18:32:50 +00:00

Support

Fix PR1329.

2007-04-14 21:50:21 +00:00

System

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Target

Change getAllocatableSet() so it returns allocatable registers for a specific register class.

2007-04-17 20:23:34 +00:00

Transforms

Spell doFinalization right, so that it is a proper virtual override and

2007-04-17 18:21:36 +00:00

VMCore

eliminate a use of Instruction::getPrev(), patch by Gabor Greif in 2005.

2007-04-17 17:36:12 +00:00

Makefile

…