[PATCH] tree-optimization/98956 Optimizing out boolean left shift

[Navid Rahimi via Gcc-patches]

Hi GCC community,

This patch will add the missed pattern described in bug 98956 [1] to the 
match.pd. The codegen and correctness proof for this pattern is here [2,3] in 
case anyone is curious. Tested on x86_64 Linux.

Tree-optimization/98956:

Adding new optimization to match.pd:
                * match.pd ((B0 << x) cmp 0) -> B0 cmp 0 : New optimization.
                * gcc.dg/tree-ssa/pr98956.c: testcase for this optimization.
                * gcc.dg/tree-ssa/pr98956-2.c: testcase for node with 
side-effect.

1) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98956
2) https://compiler-explorer.com/z/nj4PTrecW
3) https://alive2.llvm.org/ce/z/jyJAoS

Best wishes,
Navid.

0001-Tree-optimization-98956.patch
Description: 0001-Tree-optimization-98956.patch