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ffddf6ba1c
branch folding can now compile stuff like this: void foo(int W, int X, int Y, int Z) { if (W & 1) { for (; X;--X) bar(); } else if (W & 2) { for (; Y;--Y) bar(); } else if (W & 4) { for (; Z;--Z) bar(); } else if (W & 8) { for (; W;--W) bar(); } if (W) { bar(); } } contrived testcase where loops exits all end up merging together. To have the loop merges be: ... cmplw cr0, r30, r27 bne cr0, LBB1_14 ;bb38 LBB1_16: ;cond_next48.loopexit mr r27, r29 LBB1_20: ;cond_next48 cmplwi cr0, r27, 0 beq cr0, LBB1_22 ;UnifiedReturnBlock ... instead of: ... cmplw cr0, r30, r27 bne cr0, LBB1_14 ;bb38 LBB1_16: ;cond_next48.loopexit mr r27, r29 b LBB1_20 ;cond_next48 LBB1_17: ;cond_next48.loopexit1 b LBB1_20 ;cond_next48 LBB1_18: ;cond_next48.loopexit2 b LBB1_20 ;cond_next48 LBB1_19: ;cond_next48.loopexit3 LBB1_20: ;cond_next48 cmplwi cr0, r27, 0 beq cr0, LBB1_22 ;UnifiedReturnBlock ... This is CodeGen/PowerPC/branch-opt.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31006 91177308-0d34-0410-b5e6-96231b3b80d8 |
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