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llvm-mirror/test/CodeGen/AArch64/fast-isel-folding.ll
Juergen Ributzka 629f4d87cb [FastISel][AArch64] Don't fold instructions that are not in the same basic block.
This fix checks first if the instruction to be folded (e.g. sign-/zero-extend,
or shift) is in the same machine basic block as the instruction we are folding
into.

Not doing so can result in incorrect code, because the value might not be
live-out of the basic block, where the value is defined.

This fixes rdar://problem/18169495.

llvm-svn: 216700
2014-08-29 00:19:21 +00:00

55 lines
1.1 KiB
LLVM

; RUN: llc -mtriple=aarch64-apple-darwin -O0 -fast-isel-abort -verify-machineinstrs < %s
; Test that we don't fold the shift.
define i64 @fold_shift_test(i64 %a, i1 %c) {
%1 = sub i64 %a, 8
%2 = ashr i64 %1, 3
br i1 %c, label %bb1, label %bb2
bb1:
%3 = icmp ult i64 0, %2
br i1 %3, label %bb2, label %bb3
bb2:
ret i64 1
bb3:
ret i64 2
}
; Test that we don't fold the sign-extend.
define i64 @fold_sext_test1(i32 %a, i1 %c) {
%1 = sub i32 %a, 8
%2 = sext i32 %1 to i64
br i1 %c, label %bb1, label %bb2
bb1:
%3 = icmp ult i64 0, %2
br i1 %3, label %bb2, label %bb3
bb2:
ret i64 1
bb3:
ret i64 2
}
; Test that we don't fold the sign-extend.
define i64 @fold_sext_test2(i32 %a, i1 %c) {
%1 = sub i32 %a, 8
%2 = sext i32 %1 to i64
br i1 %c, label %bb1, label %bb2
bb1:
%3 = shl i64 %2, 4
ret i64 %3
bb2:
ret i64 %2
}
; Test that we clear the kill flag.
define i32 @fold_kill_test(i32 %a) {
%1 = sub i32 %a, 8
%2 = shl i32 %1, 3
%3 = icmp ult i32 0, %2
br i1 %3, label %bb1, label %bb2
bb1:
ret i32 %2
bb2:
%4 = add i32 %2, 4
ret i32 %4
}