6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-28 19:25:00 +00:00
Code Issues Projects Releases Wiki Activity

now that all the pieces are in place, teach instcombine's

Browse Source 
simplifydemandedbits to simplify instructions with *multiple
uses* in contexts where it can get away with it.  This allows
it to simplify the code in multi-use-or.ll into a single 'add 
double'.

This change is particularly interesting because it will cover
up for some common codegen bugs with large integers created due
to the recent SROA patch.  When working on fixing those bugs,
this should be disabled.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63481 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2009-01-31 08:40:03 +00:00
parent 4598c943c0
commit d1b5e3fad9
2 changed files with 82 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
test/Transforms/InstCombine/multi-use-or.ll Normal file
View File

@@ -0,0 +1,24 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {add double .sx, .sy}
; The 'or' has multiple uses, make sure that this doesn't prevent instcombine
; from propagating the extends to the truncs.
define double @ScaleObjectAdd(double %sx, double %sy, double %sz) nounwind {
entry:
%sx34 = bitcast double %sx to i64 ; <i64> [#uses=1]
%sx3435 = zext i64 %sx34 to i192 ; <i192> [#uses=1]
%sy22 = bitcast double %sy to i64 ; <i64> [#uses=1]
%sy2223 = zext i64 %sy22 to i192 ; <i192> [#uses=1]
%sy222324 = shl i192 %sy2223, 128 ; <i192> [#uses=1]
%sy222324.ins = or i192 %sx3435, %sy222324 ; <i192> [#uses=1]
%a = trunc i192 %sy222324.ins to i64 ; <i64> [#uses=1]
%b = bitcast i64 %a to double ; <double> [#uses=1]
%c = lshr i192 %sy222324.ins, 128 ; <i192> [#uses=1]
%d = trunc i192 %c to i64 ; <i64> [#uses=1]
%e = bitcast i64 %d to double ; <double> [#uses=1]
%f = add double %b, %e
; ret double %e
ret double %f
}