llvm/test/CodeGen/PowerPC/sjlj.ll
Hal Finkel 13141f04d3 [PowerPC] Fix the PPCInstrInfo::getInstrLatency implementation
PowerPC uses itineraries to describe processor pipelines (and dispatch-group
restrictions for P7/P8 cores). Unfortunately, the target-independent
implementation of TII.getInstrLatency calls ItinData->getStageLatency, and that
looks for the largest cycle count in the pipeline for any given instruction.
This, however, yields the wrong answer for the PPC itineraries, because we
don't encode the full pipeline. Because the functional units are fully
pipelined, we only model the initial stages (there are no relevant hazards in
the later stages to model), and so the technique employed by getStageLatency
does not really work. Instead, we should take the maximum output operand
latency, and that's what PPCInstrInfo::getInstrLatency now does.

This caused some test-case churn, including two unfortunate side effects.
First, the new arrangement of copies we get from function parameters now
sometimes blocks VSX FMA mutation (a FIXME has been added to the code and the
test cases), and we have one significant test-suite regression:

SingleSource/Benchmarks/BenchmarkGame/spectral-norm
	56.4185% +/- 18.9398%

In this benchmark we have a loop with a vectorized FP divide, and it with the
new scheduling both divides end up in the same dispatch group (which in this
case seems to cause a problem, although why is not exactly clear). The grouping
structure is hard to predict from the bottom of the loop, and there may not be
much we can do to fix this.

Very few other test-suite performance effects were really significant, but
almost all weakly favor this change. However, in light of the issues
highlighted above, I've left the old behavior available via a
command-line flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242188 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-14 20:02:02 +00:00

161 lines
5.0 KiB
LLVM

; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 | FileCheck %s
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=a2 | FileCheck -check-prefix=CHECK-NOAV %s
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
%struct.__jmp_buf_tag = type { [64 x i64], i32, %struct.__sigset_t, [8 x i8] }
%struct.__sigset_t = type { [16 x i64] }
@env_sigill = internal global [1 x %struct.__jmp_buf_tag] zeroinitializer, align 16
define void @foo() #0 {
entry:
call void @llvm.eh.sjlj.longjmp(i8* bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8*))
unreachable
; CHECK: @foo
; CHECK: addis [[REG:[0-9]+]], 2, env_sigill@toc@ha
; CHECK: addi [[REG]], [[REG]], env_sigill@toc@l
; CHECK: ld 31, 0([[REG]])
; CHECK: ld [[REG2:[0-9]+]], 8([[REG]])
; CHECK-DAG: ld 1, 16([[REG]])
; CHECK-DAG: mtctr [[REG2]]
; CHECK-DAG: ld 30, 32([[REG]])
; CHECK-DAG: ld 2, 24([[REG]])
; CHECK: bctr
return: ; No predecessors!
ret void
}
declare void @llvm.eh.sjlj.longjmp(i8*) #1
define signext i32 @main() #0 {
entry:
%retval = alloca i32, align 4
store i32 0, i32* %retval
%0 = call i8* @llvm.frameaddress(i32 0)
store i8* %0, i8** bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8**)
%1 = call i8* @llvm.stacksave()
store i8* %1, i8** getelementptr (i8*, i8** bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8**), i32 2)
%2 = call i32 @llvm.eh.sjlj.setjmp(i8* bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8*))
%tobool = icmp ne i32 %2, 0
br i1 %tobool, label %if.then, label %if.else
if.then: ; preds = %entry
store i32 1, i32* %retval
br label %return
if.else: ; preds = %entry
call void @foo()
br label %if.end
if.end: ; preds = %if.else
store i32 0, i32* %retval
br label %return
return: ; preds = %if.end, %if.then
%3 = load i32, i32* %retval
ret i32 %3
; FIXME: We should be saving VRSAVE on Darwin, but we're not!
; CHECK: @main
; CHECK: std
; Make sure that we're not saving VRSAVE on non-Darwin:
; CHECK-NOT: mfspr
; CHECK-DAG: stfd
; CHECK-DAG: stvx
; CHECK-DAG: addis [[REG:[0-9]+]], 2, env_sigill@toc@ha
; CHECK-DAG: std 31, env_sigill@toc@l([[REG]])
; CHECK-DAG: addi [[REGA:[0-9]+]], [[REG]], env_sigill@toc@l
; CHECK-DAG: std [[REGA]], [[OFF:[0-9]+]](31) # 8-byte Folded Spill
; CHECK-DAG: std 1, 16([[REGA]])
; CHECK-DAG: std 2, 24([[REGA]])
; CHECK: bcl 20, 31, .LBB1_1
; CHECK: li 3, 1
; CHECK: #EH_SjLj_Setup .LBB1_1
; CHECK: b .LBB1_2
; CHECK: .LBB1_1:
; CHECK: mflr [[REGL:[0-9]+]]
; CHECK: ld [[REG2:[0-9]+]], [[OFF]](31) # 8-byte Folded Reload
; CHECK: std [[REGL]], 8([[REG2]])
; CHECK: li 3, 0
; CHECK: .LBB1_2:
; CHECK: lfd
; CHECK: lvx
; CHECK: ld
; CHECK: blr
; CHECK-NOAV: @main
; CHECK-NOAV-NOT: stvx
; CHECK-NOAV: bcl
; CHECK-NOAV: mflr
; CHECK-NOAV: bl foo
; CHECK-NOAV-NOT: lvx
; CHECK-NOAV: blr
}
define signext i32 @main2() #0 {
entry:
%a = alloca i8, align 64
call void @bar(i8* %a)
%retval = alloca i32, align 4
store i32 0, i32* %retval
%0 = call i8* @llvm.frameaddress(i32 0)
store i8* %0, i8** bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8**)
%1 = call i8* @llvm.stacksave()
store i8* %1, i8** getelementptr (i8*, i8** bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8**), i32 2)
%2 = call i32 @llvm.eh.sjlj.setjmp(i8* bitcast ([1 x %struct.__jmp_buf_tag]* @env_sigill to i8*))
%tobool = icmp ne i32 %2, 0
br i1 %tobool, label %if.then, label %if.else
if.then: ; preds = %entry
store i32 1, i32* %retval
br label %return
if.else: ; preds = %entry
call void @foo()
br label %if.end
if.end: ; preds = %if.else
store i32 0, i32* %retval
br label %return
return: ; preds = %if.end, %if.then
%3 = load i32, i32* %retval
ret i32 %3
; CHECK: @main2
; CHECK: addis [[REG:[0-9]+]], 2, env_sigill@toc@ha
; CHECK-DAG: std 31, env_sigill@toc@l([[REG]])
; CHECK-DAG: addi [[REGB:[0-9]+]], [[REG]], env_sigill@toc@l
; CHECK-DAG: std [[REGB]], [[OFF:[0-9]+]](31) # 8-byte Folded Spill
; CHECK-DAG: std 1, 16([[REGB]])
; CHECK-DAG: std 2, 24([[REGB]])
; CHECK-DAG: std 30, 32([[REGB]])
; CHECK: bcl 20, 31,
; CHECK: blr
}
declare void @bar(i8*) #3
declare i8* @llvm.frameaddress(i32) #2
declare i8* @llvm.stacksave() #3
declare i32 @llvm.eh.sjlj.setjmp(i8*) #3
attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { noreturn nounwind }
attributes #2 = { nounwind readnone }
attributes #3 = { nounwind }