freebsd-dev/contrib/llvm/patches/patch-25-llvm-r224890-ppc-ctr-tls-loop.diff
Dimitry Andric 9cac79b378 Upgrade our copy of clang and llvm to 3.5.1 release. This is a bugfix
only release, no new features have been added.

Please note that this version requires C++11 support to build; see
UPDATING for more information.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.5.1/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.5.1/tools/clang/docs/ReleaseNotes.html>

MFC after:	1 month
X-MFC-With:	276479
2015-01-18 14:14:47 +00:00

96 lines
3.0 KiB
Diff

Pull in r224890 from upstream llvm trunk (by David Majnemer):
PowerPC: CTR shouldn't fire if a TLS call is in the loop
Determining the address of a TLS variable results in a function call in
certain TLS models. This means that a simple ICmpInst might actually
result in invalidating the CTR register.
In such cases, do not attempt to rely on the CTR register for loop
optimization purposes.
This fixes PR22034.
Differential Revision: http://reviews.llvm.org/D6786
This fixes a "Invalid PPC CTR loop" error when compiling parts of libc
for PowerPC-32.
Introduced here: http://svnweb.freebsd.org/changeset/base/276324
Index: lib/Target/PowerPC/PPCCTRLoops.cpp
===================================================================
--- lib/Target/PowerPC/PPCCTRLoops.cpp
+++ lib/Target/PowerPC/PPCCTRLoops.cpp
@@ -194,6 +194,21 @@ static bool isLargeIntegerTy(bool Is32Bit, Type *T
return false;
}
+// 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 auto *GV = dyn_cast<GlobalValue>(MemAddr);
+ if (!GV)
+ return false;
+ if (!GV->isThreadLocal())
+ return false;
+ if (!TM)
+ return true;
+ TLSModel::Model Model = TM->getTLSModel(GV);
+ return Model == TLSModel::GeneralDynamic || Model == TLSModel::LocalDynamic;
+}
+
bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) {
for (BasicBlock::iterator J = BB->begin(), JE = BB->end();
J != JE; ++J) {
@@ -390,6 +405,9 @@ bool PPCCTRLoops::mightUseCTR(const Triple &TT, Ba
SI->getNumCases()+1 >= (unsigned) TLI->getMinimumJumpTableEntries())
return true;
}
+ for (Value *Operand : J->operands())
+ if (memAddrUsesCTR(TM, Operand))
+ return true;
}
return false;
Index: test/CodeGen/PowerPC/ctrloops.ll
===================================================================
--- test/CodeGen/PowerPC/ctrloops.ll
+++ test/CodeGen/PowerPC/ctrloops.ll
@@ -1,6 +1,6 @@
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-v128:128:128-n32:64"
target triple = "powerpc64-unknown-freebsd10.0"
-; RUN: llc < %s -march=ppc64 | FileCheck %s
+; RUN: llc < %s -march=ppc64 -relocation-model=pic | FileCheck %s
@a = common global i32 0, align 4
@@ -73,3 +73,26 @@ for.end:
; CHECK-NOT: cmplwi
; CHECK: bdnz
}
+
+@tls_var = external thread_local global i8
+
+define i32 @test4() {
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %phi = phi i32 [ %dec, %for.body ], [ undef, %entry ]
+ %load = ptrtoint i8* @tls_var to i32
+ %dec = add i32 %phi, -1
+ %cmp = icmp sgt i32 %phi, 1
+ br i1 %cmp, label %for.body, label %return
+
+return: ; preds = %for.body
+ ret i32 %load
+; CHECK-LABEL: @test4
+; CHECK-NOT: mtctr
+; CHECK: addi {{[0-9]+}}
+; CHECK: cmpwi
+; CHECK-NOT: bdnz
+; CHECK: bgt
+}