[PATCH] D156055: [NewGVN][PHIOFOPS] Relax conditions when checking safety of memory accesses
Konstantina Mitropoulou via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Jul 28 01:23:44 PDT 2023
kmitropoulou added a comment.
LGTM :)
================
Comment at: llvm/lib/Transforms/Scalar/NewGVN.cpp:2649
+ // Clobbering MemoryPhi - unsafe.
+ // Note : Only checking memory phis allows us to skip constant stores
+ if (isa<MemoryPhi>(MemAccess) &&
----------------
Can you please give us more details?
In the following example, the load depends on a memory phi. But, the check in line 2651 rejects phi-of-ops optimization. This can be optimized If we do some changes in findPHIOfOpsLeader().
define i32 @mytest(ptr %p, ptr %q, i1 %cond1, i32 %TC){
entry:
br label %loop.header
loop.header:
%phi = phi i32 [0, %entry], [%ind, %loop.latch]
br i1 %cond1, label %bb1, label %bb2
bb1:
store i32 100, ptr %p
br label %loop.latch
bb2:
store i32 10, ptr %p
br label %loop.latch
loop.latch:
%phi2 = phi i32 [1, %bb1], [0, %bb2]
%ld = load i32, ptr %p
%mul = mul i32 %ld, %phi2
%ind = add i32 %phi, 1
%cond2 = icmp ule i32 %ind, %TC
br i1 %cond2, label %loop.header, label %exit
exit:
ret i32 %mul
}
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D156055/new/
https://reviews.llvm.org/D156055
More information about the llvm-commits
mailing list