On 09/14/2017 11:35 AM, Segher Boessenkool wrote: > On Thu, Sep 14, 2017 at 10:18:55AM -0500, Pat Haugen wrote: >> --- gcc/config/rs6000/rs6000.c (revision 252029) >> +++ gcc/config/rs6000/rs6000.c (working copy) >> @@ -37807,6 +37807,11 @@ rs6000_set_up_by_prologue (struct hard_r >> add_to_hard_reg_set (&set->set, Pmode, RS6000_PIC_OFFSET_TABLE_REGNUM); >> if (cfun->machine->split_stack_argp_used) >> add_to_hard_reg_set (&set->set, Pmode, 12); >> + >> + /* Make sure the hard reg set doesn't include r2, which was possibly added >> + via PIC_OFFSET_TABLE_REGNUM. */ >> + if (TARGET_TOC) >> + remove_from_hard_reg_set (&set->set, Pmode, TOC_REGNUM); >> } > Hrm, can't you simply not add it in the first place? Just a few lines up?
As we discussed offline, that is RS6000_PIC_OFFSET_TABLE_REGNUM (i.e. r30). PIC_OFFSET_REGNUM is added in shrink-wrap.c:try_shrink_wrapping(). I noticed that the test fails on 32-bit because there's no prologue and hence no shrink-wrapping to be performed. Following is updated testcase which limits it to 64-bit. Ok? -Pat Index: gcc/testsuite/gcc.target/powerpc/r2_shrink-wrap.c =================================================================== --- gcc/testsuite/gcc.target/powerpc/r2_shrink-wrap.c (nonexistent) +++ gcc/testsuite/gcc.target/powerpc/r2_shrink-wrap.c (working copy) @@ -0,0 +1,17 @@ +/* { dg-do compile { target { lp64 } } } */ +/* { dg-options "-O2 -fdump-rtl-pro_and_epilogue" } */ + +/* Verify we move the prologue past the TOC reference of 'j' and shrink-wrap + the function. */ +void bar(); +int j; +void foo(int i) +{ + j = i; + if (i > 0) + { + bar(); + } +} + +/* { dg-final { scan-rtl-dump-times "Performing shrink-wrapping" 1 "pro_and_epilogue" } } */