[llvm-branch-commits] [llvm] [BPF] expand cttz, ctlz for i32, i64 (PR #73668)

[via llvm-branch-commits]

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@@ -0,0 +1,304 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc < %s -march=bpf | FileCheck %s
+
+; test that we can expand CTTZ & CTLZ
+
+declare i32 @llvm.cttz.i32(i32, i1)
+
+define i32 @cttz_i32_zdef(i32 %a) {
+; CHECK-LABEL: cttz_i32_zdef:
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eddyz87 wrote:

Question, how stable are these expansions?
Previously compiler would just error out, maybe just insert some dummy checks that verify that something is returned from these functions? And we can add a few tests on kernel side that verify runtime result. Wdyt?

https://github.com/llvm/llvm-project/pull/73668