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llvm-mirror/test/CodeGen/X86/inreg.ll
Reid Kleckner 277138a332 [FastISel] Disable local value sinking by default
This is causing compilation timeouts on code with long sequences of
local values and calls (i.e. foo(1); foo(2); foo(3); ...).  It turns out
that code coverage instrumentation is a great way to create sequences
like this, which how our users ran into the issue in practice.

Intel has a tool that detects these kinds of non-linear compile time
issues, and Andy Kaylor reported it as PR37010.

The current sinking code scans the whole basic block once per local
value sink, which happens before emitting each call. In theory, local
values should only be introduced to be used by instructions between the
current flush point and the last flush point, so we should only need to
scan those instructions.

llvm-svn: 329822
2018-04-11 16:03:07 +00:00

47 lines
1.2 KiB
LLVM

; RUN: llc -fast-isel-sink-local-values < %s -mtriple=i686-pc-linux -mcpu=corei7 | FileCheck --check-prefix=DAG %s
; RUN: llc -fast-isel-sink-local-values < %s -mtriple=i686-pc-linux -mcpu=corei7 -O0 | FileCheck --check-prefix=FAST %s
%struct.s1 = type { double, float }
define void @g1() nounwind {
entry:
%tmp = alloca %struct.s1, align 4
call void @f(%struct.s1* inreg sret %tmp, i32 inreg 41, i32 inreg 42, i32 43)
ret void
; DAG-LABEL: g1:
; DAG: subl $[[AMT:.*]], %esp
; DAG-NEXT: $43, (%esp)
; DAG-NEXT: leal 16(%esp), %eax
; DAG-NEXT: movl $41, %edx
; DAG-NEXT: movl $42, %ecx
; DAG-NEXT: calll f
; DAG-NEXT: addl $[[AMT]], %esp
; DAG-NEXT: ret
; FAST-LABEL: g1:
; FAST: subl $[[AMT:.*]], %esp
; FAST-NEXT: leal 16(%esp), %eax
; FAST-NEXT: movl $41, %edx
; FAST-NEXT: movl $42, %ecx
; FAST: $43, (%esp)
; FAST: calll f
; FAST-NEXT: addl $[[AMT]], %esp
; FAST: ret
}
declare void @f(%struct.s1* inreg sret, i32 inreg, i32 inreg, i32)
%struct.s2 = type {}
define void @g2(%struct.s2* inreg sret %agg.result) nounwind {
entry:
ret void
; DAG: g2
; DAG-NOT: ret $4
; DAG: .size g2
; FAST: g2
; FAST-NOT: ret $4
; FAST: .size g2
}