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