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r242226 - in /branches/ARM/sve-branch/gcc: doc/...
- From: rsandifo at gcc dot gnu dot org
- To: gcc-cvs at gcc dot gnu dot org
- Date: Fri, 11 Nov 2016 17:22:34 -0000
- Subject: r242226 - in /branches/ARM/sve-branch/gcc: doc/...
Date: Fri Nov 11 17:22:32 2016
New Revision: 242226
Add DWARF support for polynomial offsets
This patch adds support for DWARF location expressions
that involve polynomial offsets. It adds a target hook that
says how the runtime invariants used in the offsets should be
represented in DWARF. SVE vectors have to be a multiple of
128 bits in size, so the GCC port uses the number of 128-bit
blocks minus one as the runtime invariant. However, in DWARF,
the vector length is exposed via a pseudo "VG" register that
holds the number of 64-bit elements in a vector. Thus:
indeterminate 1 == (VG / 2) - 1
The hook needs to be general enough to express this.
Note that in most cases the division and subtraction fold
away into surrounding expressions.