[llvm] [llvm][lto] Precommit test for libcall internalization (PR #135705)

[Arthur Eubanks via llvm-commits]

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@@ -0,0 +1,37 @@
+;; This test comes from a real world scenario in LTO, where the
+;; definition of bcmp is deleted because it has no uses, but later instcombine
+;; re-introduces a call to bcmp() as part of SimplifyLibCalls.
+
+; RUN: opt %s -o %t -module-summary -mtriple riscv32-unknown-linux-musl
+; RUN: llvm-lto2 run -o %t2 \
+; RUN:   -r %t,foo,plx \
+; RUN:   -r %t,memcmp,x \
+; RUN:   -r %t,bcmp,pl %t -save-temps
+; RUN: llvm-dis %t2.1.2.internalize.bc -o - \
+; RUN:   | FileCheck %s --check-prefix=INTERNALIZE
+; RUN: opt %t2.1.2.internalize.bc -passes=instcombine -o - -S \
+; RUN:   | FileCheck %s --check-prefix=OPTIMIZE
+
+define i1 @foo(ptr %0, [2 x i32] %1) {
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aeubanks wrote:

can this test just check if we delete `bcmp`'s definition? the instcombine on `foo` part of the test seems unnecessary IIUC

https://github.com/llvm/llvm-project/pull/135705