[GlobalISel] Fix a check that aligned tail call is lowered (llvm#82016)

Despite of a valid tail call opportunity, backends still may not
generate a tail call or such lowering is not implemented yet.

Check that lowering has happened instead of its possibility when
generating G_ASSERT_ALIGN.

Author: e-kud

llvm/lib/CodeGen/GlobalISel/CallLowering.cpp

@@ -187,7 +187,7 @@ bool CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, const CallBase &CB,
   if (!lowerCall(MIRBuilder, Info))
     return false;
 
-  if (ReturnHintAlignReg && !Info.IsTailCall) {
+  if (ReturnHintAlignReg && !Info.LoweredTailCall) {
     MIRBuilder.buildAssertAlign(ResRegs[0], ReturnHintAlignReg,
                                 ReturnHintAlign);
   }

llvm/test/CodeGen/X86/GlobalISel/calllowering-tailcall.ll

@@ -0,0 +1,24 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc -mtriple=x86_64-linux-gnu -global-isel < %s | FileCheck %s --check-prefix=X64
+; RUN: llc -mtriple=i686-linux-gnu -global-isel < %s | FileCheck %s --check-prefix=X86
+
+declare ptr @foo()
+
+define ptr @aligned_tailcall() nounwind {
+; X64-LABEL: aligned_tailcall:
+; X64:       # %bb.0: # %entry
+; X64-NEXT:    pushq %rax
+; X64-NEXT:    callq foo
+; X64-NEXT:    popq %rcx
+; X64-NEXT:    retq
+;
+; X86-LABEL: aligned_tailcall:
+; X86:       # %bb.0: # %entry
+; X86-NEXT:    subl $12, %esp
+; X86-NEXT:    calll foo
+; X86-NEXT:    addl $12, %esp
+; X86-NEXT:    retl
+entry:
+  %call = tail call align 8 ptr @foo()
+  ret ptr %call
+}