[llvm] [GVN] Teach GVN simple masked load/store forwarding (PR #157689)

[David Sherwood via llvm-commits]

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@@ -36,6 +36,152 @@ define <128 x i8> @f1(ptr %a0, <128 x i8> %a1, <128 x i8> %a2) {
   ret <128 x i8> %v4
 }
 
-declare <128 x i8> @llvm.masked.load.v128i8.p0(ptr, i32, <128 x i1>, <128 x i8>)
-declare void @llvm.masked.store.v128i8.p0(<128 x i8>, ptr, i32, <128 x i1>)
+define <4 x float> @forward_masked_load(ptr %0, ptr %1) {
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david-arm wrote:

Might be worth having a test for an arbitrary mask as well that's passed in as a function argument, i.e. we can apply the optimisation even if the mask isn't known to come from get.active.lane.mask.

https://github.com/llvm/llvm-project/pull/157689