mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-12-04 01:11:44 +00:00
84aea79e47
Adds a test to verify the behavior that r233153 restored: 'optnone' does not spuriously disable the DAG combiner, and in fact there are cases where the DAG combiner must run (even at -O0 or 'optnone') in order for codegen to succeed. Differential Revision: http://reviews.llvm.org/D8614 llvm-svn: 233584
74 lines
2.6 KiB
LLVM
74 lines
2.6 KiB
LLVM
; RUN: llc < %s -mtriple=x86_64-pc-win32 -O0 -mattr=+avx | FileCheck %s
|
|
|
|
; Background:
|
|
; If fast-isel bails out to normal selection, then the DAG combiner will run,
|
|
; even at -O0. In principle this should not happen (those are optimizations,
|
|
; and we said -O0) but as a practical matter there are some instruction
|
|
; selection patterns that depend on the legalizations and transforms that the
|
|
; DAG combiner does.
|
|
;
|
|
; The 'optnone' attribute implicitly sets -O0 and fast-isel for the function.
|
|
; The DAG combiner was disabled for 'optnone' (but not -O0) by r221168, then
|
|
; re-enabled in r233153 because of problems with instruction selection patterns
|
|
; mentioned above. (Note: because 'optnone' is supposed to match -O0, r221168
|
|
; really should have disabled the combiner for both.)
|
|
;
|
|
; If instruction selection eventually becomes smart enough to run without DAG
|
|
; combiner, then the combiner can be turned off for -O0 (not just 'optnone')
|
|
; and this test can go away. (To be replaced by a different test that verifies
|
|
; the DAG combiner does *not* run at -O0 or for 'optnone' functions.)
|
|
;
|
|
; In the meantime, this test wants to make sure the combiner stays enabled for
|
|
; 'optnone' functions, just as it is for -O0.
|
|
|
|
|
|
; The test cases @foo[WithOptnone] prove that the same DAG combine happens
|
|
; with -O0 and with 'optnone' set. To prove this, we use a Windows triple to
|
|
; cause fast-isel to bail out (because something about the calling convention
|
|
; is not handled in fast-isel). Then we have a repeated fadd that can be
|
|
; combined into an fmul. We show that this happens in both the non-optnone
|
|
; function and the optnone function.
|
|
|
|
define float @foo(float %x) #0 {
|
|
entry:
|
|
%add = fadd fast float %x, %x
|
|
%add1 = fadd fast float %add, %x
|
|
ret float %add1
|
|
}
|
|
|
|
; CHECK-LABEL: @foo
|
|
; CHECK-NOT: add
|
|
; CHECK: mul
|
|
; CHECK-NEXT: ret
|
|
|
|
define float @fooWithOptnone(float %x) #1 {
|
|
entry:
|
|
%add = fadd fast float %x, %x
|
|
%add1 = fadd fast float %add, %x
|
|
ret float %add1
|
|
}
|
|
|
|
; CHECK-LABEL: @fooWithOptnone
|
|
; CHECK-NOT: add
|
|
; CHECK: mul
|
|
; CHECK-NEXT: ret
|
|
|
|
|
|
; The test case @bar is derived from an instruction selection failure case
|
|
; that was solved by r233153. It depends on -mattr=+avx.
|
|
; Really all we're trying to prove is that it doesn't crash any more.
|
|
|
|
@id84 = common global <16 x i32> zeroinitializer, align 64
|
|
|
|
define void @bar() #1 {
|
|
entry:
|
|
%id83 = alloca <16 x i8>, align 16
|
|
%0 = load <16 x i32>, <16 x i32>* @id84, align 64
|
|
%conv = trunc <16 x i32> %0 to <16 x i8>
|
|
store <16 x i8> %conv, <16 x i8>* %id83, align 16
|
|
ret void
|
|
}
|
|
|
|
attributes #0 = { "unsafe-fp-math"="true" }
|
|
attributes #1 = { noinline optnone "unsafe-fp-math"="true" }
|