Hello, > Isn't it the case that *any* conversion can be stripped for the purpose > of this routine? I get an ICE compiling the Ada RTS a-strfix.adb because > of that. The following seems to fix it, but is it right?
no, it is not. The uses of constant_multiple_of expect that it determines whether TOP = CST * BOT, except for no-op casts. It is true that there are some sequences of casts that in the end satisfy this, but are not handled by constant_multiple_of, but you would need to be more careful when changing it. The bug you describe most probably is PR 21963 (and there is a patch for this PR submitted). Zdenek > *** tree-ssa-loop-ivopts.c 26 Jun 2005 21:21:32 -0000 2.82 > --- tree-ssa-loop-ivopts.c 29 Jun 2005 21:38:29 -0000 > *************** constant_multiple_of (tree type, tree to > *** 2594,2599 **** > bool negate; > > ! STRIP_NOPS (top); > ! STRIP_NOPS (bot); > > if (operand_equal_p (top, bot, 0)) > --- 2594,2603 ---- > bool negate; > > ! /* For determining the condition above, we can ignore all conversions, not > ! just those that don't change the mode, so can't use STRIP_NOPS here. */ > ! while (TREE_CODE (top) == NOP_EXPR || TREE_CODE (top) == CONVERT_EXPR) > ! top = TREE_OPERAND (top, 0); > ! while (TREE_CODE (bot) == NOP_EXPR || TREE_CODE (bot) == CONVERT_EXPR) > ! bot = TREE_OPERAND (bot, 0); > > if (operand_equal_p (top, bot, 0))
