[llvm] [X86] Do not elect to tail call if caller must preserve all registers (PR #112098)

[Antonio Frighetto via llvm-commits]

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@@ -0,0 +1,34 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -mtriple=x86_64-linux-gnu -mattr=-sse,-avx | FileCheck %s
+
+ at .str = private unnamed_addr constant [6 x i8] c"%d %d\00", align 1
+
+define void @caller(i32 %0, i32 %1) #0 {
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antoniofrighetto wrote:

>From what I can tell, this seems like something that ought to be done, it doesn't seem to be mandatory (from the user standpoint). Also, it looks orthogonal to the current issue, i.e., we shouldn't tail call regardless of the presence of the attribute in the callee or compiled with `-mgeneral-regs-only` (note that, unlike GCC, Clang is fine without -mgeneral-regs-only).

https://github.com/llvm/llvm-project/pull/112098