Access chain indices are always interpreted as signed integers.
So use signed clamp instead of unsigned clamp. We must also
clamp to the max signed int for the index type.
Fixes#3072
spirv-opt: Add --graphics-robust-access
Clamps access chain indices so they are always
in bounds.
Assumes:
- Logical addressing mode
- No runtime-array-descriptor-indexing
- No variable pointers
Adds stub code for clamping coordinate and samples
for OpImageTexelPointer.
Adds SinglePassRunAndFail optimizer test fixture.
Android.mk: add source/opt/graphics_robust_access_pass.cpp
Adds Constant::GetSignExtendedValue, Constant::GetZeroExtendedValue
