Commit 88a395a1 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r251582: 

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r251582 | hfinkel | 2015-10-28 19:43:00 -0400 (Wed, 28 Oct 2015) | 11 lines

[PowerPC] Recurse through constants when looking for TLS globals

We cannot form ctr-based loops around function calls, including calls to
__tls_get_addr used for PIC TLS variables. References to such TLS variables,
however, might be buried within constant expressions, and so we need to search
the entire constant expression to be sure that no references to such TLS
variables exist.

Fixes PR25256, reported by Eric Schweitz. This is a slightly-modified version
of the patch suggested by Eric in the bug report, and a test case I created.

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llvm-svn: 253120
parent 10699231

llvm/lib/Target/PowerPC/PPCCTRLoops.cpp

+10 −2
Original line number Diff line number Diff line
@@ -197,10 +197,18 @@ static bool isLargeIntegerTy(bool Is32Bit, Type *Ty) { 
// Determining the address of a TLS variable results in a function call in

// certain TLS models.

static bool memAddrUsesCTR(const PPCTargetMachine *TM,

                           const llvm::Value *MemAddr) {

                           const Value *MemAddr) {

  const auto *GV = dyn_cast<GlobalValue>(MemAddr);

  if (!GV)

  if (!GV) {

    // Recurse to check for constants that refer to TLS global variables.

    if (const auto *CV = dyn_cast<Constant>(MemAddr))

      for (const auto &CO : CV->operands())

        if (memAddrUsesCTR(TM, CO))

          return true;



    return false;

  }



  if (!GV->isThreadLocal())

    return false;

  if (!TM)

llvm/test/CodeGen/PowerPC/ctr-loop-tls-const.ll

0 → 100644
+40 −0
Original line number Diff line number Diff line 
; RUN: llc -mcpu=pwr7 -relocation-model=pic < %s | FileCheck %s

target datalayout = "E-m:e-i64:64-n32:64"

target triple = "powerpc64-unknown-linux-gnu"



@x = thread_local global [1600 x i32] zeroinitializer, align 4



; Function Attrs: nounwind

define void @foo(i32 signext %v) #0 {

entry:

  br label %vector.body



vector.body:                                      ; preds = %vector.body, %entry

  %index = phi i64 [ 0, %entry ], [ %index.next, %vector.body ]

  %induction5 = or i64 %index, 1

  %0 = getelementptr inbounds [1600 x i32], [1600 x i32]* @x, i64 0, i64 %index

  %1 = getelementptr inbounds [1600 x i32], [1600 x i32]* @x, i64 0, i64 %induction5

  %2 = load i32, i32* %0, align 4

  %3 = load i32, i32* %1, align 4

  %4 = add nsw i32 %2, %v

  %5 = add nsw i32 %3, %v

  store i32 %4, i32* %0, align 4

  store i32 %5, i32* %1, align 4

  %index.next = add i64 %index, 2

  %6 = icmp eq i64 %index.next, 1600

  br i1 %6, label %for.cond.cleanup, label %vector.body



for.cond.cleanup:                                 ; preds = %vector.body

  ret void

}



; CHECK-LABEL: @foo

; CHECK-NOT: mtctr

; CHECK: __tls_get_addr



attributes #0 = { nounwind }



!llvm.module.flags = !{!0}



!0 = !{i32 1, !"PIC Level", i32 2}