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...but it looks like JumpThreading at > least attempts to thread across indirect branches. You can either try > to fix it or file a bug with your test case. In the source it says "If the predecessor is an indirect goto, we can't split the edge. <http://llvm.org/docs/doxygen/html/JumpThreading_8cpp_source.html#l00914>" Why would that be the case? -- Carlo Alberto Ferraris <cafxx at strayorange.com <mailto:cafxx at strayorange.com>> website/blog <http://cafxx.strayorange.com> - +39 333 7643 235 -------------- next part -------------- An HTML attachment was scrubbed... URL...

...t;> least attempts to thread across indirect branches. You can either try >>> to fix it or file a bug with your test case. >> In the source it says "If the predecessor is an indirect goto, we >> can't split the edge. >> <http://llvm.org/docs/doxygen/html/JumpThreading_8cpp_source.html#l00914>" >> Why would that be the case? > > Splitting an edge creates a block which executes when leaving a > specific block to go to a specific successor. The only way to split an > indirect goto is to insert code before the jump which checks for a > specific de...

On Jul 7, 2011, at 2:05 AM, Carlo Alberto Ferraris wrote: > Consider this IR fragment produced after -O3: >> %7: >> %8 = phi i8* [ blockaddress(@0, %19), %19 ], [ %12, %11 ] >> %9 = phi i32 [ %20, %19 ], [ 0, %11 ] >> indirectbr i8* %8, [label %4, label %19] >> >> %19: >> %20 = add nsw i32 %9, 1 >> %21 = icmp eq i32 %9, 9999 >> br i1 %21,

Consider this IR fragment produced after -O3: > %7: > %8 = phi i8* [ blockaddress(@0, %19), %19 ], [ %12, %11 ] > %9 = phi i32 [ %20, %19 ], [ 0, %11 ] > indirectbr i8* %8, [label %4, label %19] > > %19: > %20 = add nsw i32 %9, 1 > %21 = icmp eq i32 %9, 9999 > br i1 %21, label %16, label %7 the br in %19 should be optimized to branch directly to itself rather than going

On Jul 7, 2011, at 4:33 AM, Carlo Alberto Ferraris wrote: > Il 07/07/2011 11:14, Cameron Zwarich ha scritto: >> >> I haven't read the code in detail, but it looks like JumpThreading at least attempts to thread across indirect branches. You can either try to fix it or file a bug with your test case. > In the source it says "If the predecessor is an indirect goto, we

..., but it looks like JumpThreading at least attempts to thread across indirect branches. You can either try to fix it or file a bug with your test case. >>> In the source it says "If the predecessor is an indirect goto, we can't split the edge. <http://llvm.org/docs/doxygen/html/JumpThreading_8cpp_source.html#l00914>" Why would that be the case? >> Splitting an edge creates a block which executes when leaving a >> specific block to go to a specific successor. The only way to split an >> indirect goto is to insert code before the jump which checks for a >> specific de...