On Tue, May 20, 2014 at 3:28 PM, Peter Bergner <berg...@vnet.ibm.com> wrote: > The following patch fixes a semi-latent bug for the HTM pattern used with > the __builtin_ttest() builtin. This is supposed to expand to a tabortwci. > instruction which sets cr0 and then some code that copies the cr0 value > into a gpr and then shifts and masks it into the lowest 2 bits in the gpr. > > With newish -mcpu targets, we generate a "mfocrf rX,128" to copy the cr0 > value into bits 32-35 of the gpr. However, in some cases, we will instead > generate a "mfcr rX" instruction, which copies all 8 CR fields into the > gpr, with cr0 again being in bits 32-35. The difference is that the > mfocrf instruction seems to duplicate the 4-bit CR field in the gpr, > so bits 36-39 are a duplicate of bits 32-35. The error in the ttest > pattern is that we only shift the value down 24 bits. This "works" > when a mfocrf copied the cr0 into the rgeister due the duplicated CR > field, but is wrong when a mfcr instruction is used. > > The following passed bootstrap and regtesting on powerpc64-linux. > Ok for trunk? Is this also ok for the 4.9 and 4.8 branches once > my bootstraps and regtesting is done there? > > Peter > > > gcc/ > * config/rs6000/htm.md (ttest): Use correct shift value to get CR0. > > gcc/testsuite/ > * gcc.target/powerpc/htm-ttest.c: New test.
Okay. Thanks, David
