[Bug target/105034] [10/11/12 regression]Suboptimal codegen for min/max with -Os

[wwwhhhyyy333 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105034

--- Comment #2 from Hongyu Wang <wwwhhhyyy333 at gmail dot com> ---
For -O2 stv doesn't do such transform
Computing gain for chain #1...
  Instruction gain 8 for     7: {r84:SI=smax(r85:SI,0);clobber flags:CC;}
      REG_DEAD r85:SI
      REG_UNUSED flags:CC
  Instruction conversion gain: 8
  Registers conversion cost: 12
  Total gain: -4

Since sse->integer reg move cost is 6 for generic cost.

Buf for -Os the cost is 3 so it is consider to be profitable.
Computing gain for chain #1...
  Instruction gain 8 for     7: {r84:SI=smax(r85:SI,0);clobber flags:CC;}
      REG_DEAD r85:SI
      REG_UNUSED flags:CC
  Instruction conversion gain: 8
  Registers conversion cost: 6
  Total gain: 2

FWIW, the solution would be either adjust the ix86_size cost, or blocks out 
optimize_size in the stv gate.