llvm-6502/test/CodeGen/AArch64/fast-isel-trunc.ll

; RUN: llc -mtriple=aarch64-apple-darwin -fast-isel -fast-isel-abort -verify-machineinstrs < %s

; Test that %1 doesn't get the kill flag set before its last use.
define i32 @test_trunc(i32 %a) {
  %1 = add i32 %a, 1
  %2 = trunc i32 %1 to i16
  %3 = icmp ult i16 1, %2
  %4 = add i32 %1, 1
  %5 = sext i1 %3 to i32
  %6 = and i32 %4, %5
  ret i32 %6
}
[FastISel][AArch64] Fix an incorrect kill flag due to a bug in SelectTrunc. When we select a trunc instruction we don't emit any code if the type is already i32 or smaller. This is because the instruction that uses the truncated value will deal with it. This behavior can incorrectly transfer a kill flag, which was meant for the result of the truncate, onto the source register. %2 = trunc i32 %1 to i16 ... = ... %2 -> ... = ... vreg1 <kill> ... = ... %1 ... = ... vreg1 This commit fixes this by emitting a COPY instruction, so that the result and source register are distinct virtual registers. This fixes rdar://problem/18178188. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216750 91177308-0d34-0410-b5e6-96231b3b80d8 2014-08-29 17:58:16 +00:00			`; RUN: llc -mtriple=aarch64-apple-darwin -fast-isel -fast-isel-abort -verify-machineinstrs < %s`

			`; Test that %1 doesn't get the kill flag set before its last use.`
			`define i32 @test_trunc(i32 %a) {`
			`%1 = add i32 %a, 1`
			`%2 = trunc i32 %1 to i16`
			`%3 = icmp ult i16 1, %2`
			`%4 = add i32 %1, 1`
			`%5 = sext i1 %3 to i32`
			`%6 = and i32 %4, %5`
			`ret i32 %6`
			`}`