CARD P1b (written 2026-09-26 01:17:33 -0700, before compile)  unit source/ai/path_structure_bsp  fn _structure_test_ray2d
Evidence (D, /Od fn 0x4cfe60): no byte local for the pathfinding flags - the /Od frame has only bsp, flags ptr,
pathfinding ptr, surface_result, next [ebp-0x34], per-arm passable/collision_surface and two BIT_VECTOR temps; the flags
byte is re-read by index for the `if` (+0x98..+0xa3) and again for TEST_FLAG(...,0x80) (+0xb9..+0xc7); the enter test is
spelled enter_t-first (`movss [ebp-0x2c]; comiss ...,[ebp+0x1c]; jbe` = enter_t > distance), the exit test distance-first
(`movss [ebp+0x1c]; comiss ...,[ebp-0x20]; jbe` = distance > exit_t); both guards chained with the flags read.
Proposed shape: P1 minus the `pathfinding_surface_flags` local, conditions `surface_result.enter_t > distance &&
pathfinding_surfaces[enter]` and `next == NONE && distance > exit_t && pathfinding_surfaces[exit]`, TEST_FLAG on the
re-indexed byte.
Prediction: C2 CSEs the repeated byte load (no store between) and the x87 compare canonicalises a>b / b<a identically
-> EXACT and object identical to base (p ~0.7). Failure mode: the second byte load re-issued (extra movzx) or an
fcomp operand swap (fld enter_t first) -> residual; then P1 stays the proposal.
