From 43132c46a6ca95feb959377a50e74acd8b0125c9 Mon Sep 17 00:00:00 2001
From: John Brawn <john.brawn@arm.com>
Date: Mon, 15 May 2017 11:50:21 +0000
Subject: [PATCH] [ARM] Mark LEApcrel as not having side effects

Doing this lets us hoist it out of loops, and I've also marked it as
rematerializable the same as the thumb1 and thumb2 counterparts.

It looks like it being marked as such was just a mistake, as the commit that
made that change only mentions LEApcrelJT and in thumb1 and thumb2 only the
LEApcrelJT instructions were marked as having side-effects, so it looks like
the intent was to only mark LEApcrelJT as having side-effects but LEApcrel was
accidentally marked as such also.

Differential Revision: https://reviews.llvm.org/D32857

llvm-svn: 303053
---
 llvm/lib/Target/ARM/ARMInstrInfo.td |  4 ++--
 llvm/test/CodeGen/ARM/adr-hoist.ll  | 31 +++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/CodeGen/ARM/adr-hoist.ll

diff --git a/llvm/lib/Target/ARM/ARMInstrInfo.td b/llvm/lib/Target/ARM/ARMInstrInfo.td
index d06b7d0896f1..9e33f5ced875 100644
--- a/llvm/lib/Target/ARM/ARMInstrInfo.td
+++ b/llvm/lib/Target/ARM/ARMInstrInfo.td
@@ -2222,14 +2222,14 @@ def ADR : AI1<{0,?,?,0}, (outs GPR:$Rd), (ins adrlabel:$label),
   let Inst{11-0} = label{11-0};
 }
 
-let hasSideEffects = 1 in {
+let hasSideEffects = 0, isReMaterializable = 1 in
 def LEApcrel : ARMPseudoInst<(outs GPR:$Rd), (ins i32imm:$label, pred:$p),
                     4, IIC_iALUi, []>, Sched<[WriteALU, ReadALU]>;
 
+let hasSideEffects = 1 in
 def LEApcrelJT : ARMPseudoInst<(outs GPR:$Rd),
                       (ins i32imm:$label, pred:$p),
                       4, IIC_iALUi, []>, Sched<[WriteALU, ReadALU]>;
-}
 
 //===----------------------------------------------------------------------===//
 //  Control Flow Instructions.
diff --git a/llvm/test/CodeGen/ARM/adr-hoist.ll b/llvm/test/CodeGen/ARM/adr-hoist.ll
new file mode 100644
index 000000000000..ddf6ceac7004
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/adr-hoist.ll
@@ -0,0 +1,31 @@
+; RUN: llc -mtriple=armv7a   %s -o - | FileCheck %s
+; RUN: llc -mtriple=thumbv7m %s -o - | FileCheck %s
+; RUN: llc -mtriple=thumbv6m %s -o - | FileCheck %s
+
+@arr = internal unnamed_addr constant [4 x i32] [i32 305419896, i32 -1430532899, i32 -2023406815, i32 -573785174], align 4
+
+; Check that the adr of arr is hoisted out of the loop
+; CHECK: adr [[REG:r[0-9]+]], .LCP
+; CHECK: .LBB
+; CHECK-NOT adr
+; CHECK: ldr{{(.w)?}} {{r[0-9]+}}, {{\[}}[[REG]],
+
+define void @fn(i32 %n, i32* %p) {
+entry:
+  %cmp8 = icmp sgt i32 %n, 0
+  br i1 %cmp8, label %for.body, label %for.cond.cleanup
+
+for.body:
+  %i.09 = phi i32 [ %inc, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32, i32* %p, i32 %i.09
+  %0 = load i32, i32* %arrayidx, align 4
+  %arrayidx1 = getelementptr inbounds [4 x i32], [4 x i32]* @arr, i32 0, i32 %0
+  %1 = load i32, i32* %arrayidx1, align 4
+  store i32 %1, i32* %arrayidx, align 4
+  %inc = add nuw nsw i32 %i.09, 1
+  %exitcond = icmp eq i32 %inc, %n
+  br i1 %exitcond, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+  ret void
+}