[SimplifyCFG] Be more aggressive

Up the phi node folding threshold from a cheap "1" to a meagre "2".

Update tests for extra added selects and slight code churn.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229099 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
James Molloy 2015-02-13 10:48:30 +00:00
parent 94b64060af
commit c76bff0715
3 changed files with 15 additions and 37 deletions

View File

@ -53,9 +53,13 @@ using namespace PatternMatch;
#define DEBUG_TYPE "simplifycfg"
// Chosen as 2 so as to be cheap, but still to have enough power to fold
// a select, so the "clamp" idiom (of a min followed by a max) will be caught.
// To catch this, we need to fold a compare and a select, hence '2' being the
// minimum reasonable default.
static cl::opt<unsigned>
PHINodeFoldingThreshold("phi-node-folding-threshold", cl::Hidden, cl::init(1),
cl::desc("Control the amount of phi node folding to perform (default = 1)"));
PHINodeFoldingThreshold("phi-node-folding-threshold", cl::Hidden, cl::init(2),
cl::desc("Control the amount of phi node folding to perform (default = 2)"));
static cl::opt<bool>
DupRet("simplifycfg-dup-ret", cl::Hidden, cl::init(false),

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@ -1,9 +1,9 @@
; RUN: llc -O3 -mcpu=cortex-a57 < %s | FileCheck %s
; CHECK-LABLE: @test
; CHECK: tst [[CMP:x[0-9]+]], #0x8000000000000000
; CHECK: csel [[R0:x[0-9]+]], [[S0:x[0-9]+]], [[S1:x[0-9]+]], eq
; CHECK: csel [[R1:x[0-9]+]], [[S2:x[0-9]+]], [[S3:x[0-9]+]], eq
; CHECK-LABEL: @test
; CHECK: and
; CHECK: csel
; CHECK: csel
target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
target triple = "arm64--linux-gnueabi"

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@ -135,39 +135,13 @@ define <16 x i8> @test5(<16 x i8> %arg, i32 %path) {
; In stress mode, constant vector are promoted
; Since, the constant is the same as the previous function,
; the same address must be used
; PROMOTED: adrp [[PAGEADDR:x[0-9]+]], [[CSTV1]]@PAGE
; PROMOTED-NEXT: ldr q[[REGNUM:[0-9]+]], {{\[}}[[PAGEADDR]], [[CSTV1]]@PAGEOFF]
; PROMOTED-NEXT: cbz w0, [[LABEL:LBB.*]]
; Next BB
; PROMOTED: add.16b [[DESTV:v[0-9]+]], v0, v[[REGNUM]]
; PROMOTED-NEXT: mul.16b v[[REGNUM]], [[DESTV]], v[[REGNUM]]
; Next BB
; PROMOTED-NEXT: [[LABEL]]:
; PROMOTED-NEXT: mul.16b [[TMP1:v[0-9]+]], v[[REGNUM]], v[[REGNUM]]
; PROMOTED-NEXT: mul.16b [[TMP2:v[0-9]+]], [[TMP1]], [[TMP1]]
; PROMOTED-NEXT: mul.16b [[TMP3:v[0-9]+]], [[TMP2]], [[TMP2]]
; PROMOTED-NEXT: mul.16b v0, [[TMP3]], [[TMP3]]
; PROMOTED-NEXT: ret
; PROMOTED: ldr
; PROMOTED-NOT: ldr
; PROMOTED: ret
; REGULAR-LABEL: test5:
; REGULAR: cbz w0, [[LABELelse:LBB.*]]
; Next BB
; REGULAR: adrp [[PAGEADDR:x[0-9]+]], [[CSTLABEL:lCP.*]]@PAGE
; REGULAR-NEXT: ldr q[[REGNUM:[0-9]+]], {{\[}}[[PAGEADDR]], [[CSTLABEL]]@PAGEOFF]
; REGULAR-NEXT: add.16b [[DESTV:v[0-9]+]], v0, v[[REGNUM]]
; REGULAR-NEXT: mul.16b v[[DESTREGNUM:[0-9]+]], [[DESTV]], v[[REGNUM]]
; REGULAR-NEXT: b [[LABELend:LBB.*]]
; Next BB
; REGULAR-NEXT: [[LABELelse]]
; REGULAR-NEXT: adrp [[PAGEADDR:x[0-9]+]], [[CSTLABEL:lCP.*]]@PAGE
; REGULAR-NEXT: ldr q[[DESTREGNUM]], {{\[}}[[PAGEADDR]], [[CSTLABEL]]@PAGEOFF]
; Next BB
; REGULAR-NEXT: [[LABELend]]:
; REGULAR-NEXT: mul.16b [[TMP1:v[0-9]+]], v[[DESTREGNUM]], v[[DESTREGNUM]]
; REGULAR-NEXT: mul.16b [[TMP2:v[0-9]+]], [[TMP1]], [[TMP1]]
; REGULAR-NEXT: mul.16b [[TMP3:v[0-9]+]], [[TMP2]], [[TMP2]]
; REGULAR-NEXT: mul.16b v0, [[TMP3]], [[TMP3]]
; REGULAR-NEXT: ret
; REGULAR: ldr
; REGULAR: ret
entry:
%tobool = icmp eq i32 %path, 0
br i1 %tobool, label %if.end, label %if.then