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llvm-6502/test/CodeGen/Blackfin/2009-08-15-SetCC-Undef.ll
Evan Cheng d40d03e1bd Teach dag combine to fold the following transformation more aggressively:
(OP (trunc x), (trunc y)) -> (trunc (OP x, y))

Unfortunately this simple change causes dag combine to infinite looping. The problem is the shrink demanded ops optimization tend to canonicalize expressions in the opposite manner. That is badness. This patch disable those optimizations in dag combine but instead it is done as a late pass in sdisel.

This also exposes some deficiencies in dag combine and x86 setcc / brcond lowering. Teach them to look pass ISD::TRUNCATE in various places.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92849 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-06 19:38:29 +00:00

17 lines
517 B
LLVM

; RUN: llc < %s -march=bfin -verify-machineinstrs
; An undef argument causes a setugt node to escape instruction selection.
define void @bugt() {
cond_next305:
%tmp306307 = trunc i32 undef to i8 ; <i8> [#uses=1]
%tmp308 = icmp ugt i8 %tmp306307, 6 ; <i1> [#uses=1]
br i1 %tmp308, label %bb311, label %bb314
bb311: ; preds = %cond_next305
unreachable
bb314: ; preds = %cond_next305
ret void
}