From 51ad99d2c514a8923a2519e37b43f774d95ef9a5 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Thu, 21 Jan 2010 02:09:26 +0000 Subject: Re-implement the main strength-reduction portion of LoopStrengthReduction. This new version is much more aggressive about doing "full" reduction in cases where it reduces register pressure, and also more aggressive about rewriting induction variables to count down (or up) to zero when doing so reduces register pressure. It currently uses fairly simplistic algorithms for finding reuse opportunities, but it introduces a new framework allows it to combine multiple strategies at once to form hybrid solutions, instead of doing all full-reduction or all base+index. llvm-svn: 94061 --- llvm/test/CodeGen/Thumb2/lsr-deficiency.ll | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'llvm/test/CodeGen/Thumb2/lsr-deficiency.ll') diff --git a/llvm/test/CodeGen/Thumb2/lsr-deficiency.ll b/llvm/test/CodeGen/Thumb2/lsr-deficiency.ll index 7b1b57a786e..ac2cd34e4b3 100644 --- a/llvm/test/CodeGen/Thumb2/lsr-deficiency.ll +++ b/llvm/test/CodeGen/Thumb2/lsr-deficiency.ll @@ -1,25 +1,29 @@ ; RUN: llc < %s -mtriple=thumbv7-apple-darwin10 -relocation-model=pic | FileCheck %s ; rdar://7387640 -; FIXME: We still need to rewrite array reference iv of stride -4 with loop -; count iv of stride -1. +; This now reduces to a single induction variable. + +; TODO: It still gets a GPR shuffle at the end of the loop +; This is because something in instruction selection has decided +; that comparing the pre-incremented value with zero is better +; than comparing the post-incremented value with -4. @G = external global i32 ; [#uses=2] @array = external global i32* ; [#uses=1] define arm_apcscc void @t() nounwind optsize { ; CHECK: t: -; CHECK: mov.w r2, #4000 -; CHECK: movw r3, #1001 +; CHECK: mov.w r2, #1000 entry: %.pre = load i32* @G, align 4 ; [#uses=1] br label %bb bb: ; preds = %bb, %entry ; CHECK: LBB1_1: -; CHECK: subs r3, #1 -; CHECK: cmp r3, #0 -; CHECK: sub.w r2, r2, #4 +; CHECK: cmp r2, #0 +; CHECK: sub.w r9, r2, #1 +; CHECK: mov r2, r9 + %0 = phi i32 [ %.pre, %entry ], [ %3, %bb ] ; [#uses=1] %indvar = phi i32 [ 0, %entry ], [ %indvar.next, %bb ] ; [#uses=2] %tmp5 = sub i32 1000, %indvar ; [#uses=1] -- cgit v1.2.3