[PowerPC] On PPC32, 128-bit shifts might be runtime calls

The counter-loops formation pass needs to know what operations might be
function calls (because they can't appear in counter-based loops). On PPC32,
128-bit shifts might be runtime calls (even though you can't use __int128 on
PPC32, it seems that SROA might form them).

Fixes PR19709.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208501 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCCTRLoops.cpp b/lib/Target/PowerPC/PPCCTRLoops.cpp
index 7749c08d2dc741a69df4e6bda6653d86bd6315ef..ec1e34d91f93b8b158bcab990b6701d14d6b37d5 100644 (file)
--- a/lib/Target/PowerPC/PPCCTRLoops.cpp
+++ b/lib/Target/PowerPC/PPCCTRLoops.cpp
@@ -370,6 +370,14 @@ bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) {
                 J->getOpcode() == Instruction::URem ||
                 J->getOpcode() == Instruction::SRem)) {
       return true;
+    } else if (TT.isArch32Bit() &&
+               isLargeIntegerTy(false, J->getType()->getScalarType()) &&
+               (J->getOpcode() == Instruction::Shl ||
+                J->getOpcode() == Instruction::AShr ||
+                J->getOpcode() == Instruction::LShr)) {
+      // Only on PPC32, for 128-bit integers (specifically not 64-bit
+      // integers), these might be runtime calls.
+      return true;
     } else if (isa<IndirectBrInst>(J) || isa<InvokeInst>(J)) {
       // On PowerPC, indirect jumps use the counter register.
       return true;

diff --git a/test/CodeGen/PowerPC/ctrloop-sh.ll b/test/CodeGen/PowerPC/ctrloop-sh.ll
new file mode 100644 (file)
index 0000000..d8e6fc7
--- /dev/null
+++ b/test/CodeGen/PowerPC/ctrloop-sh.ll
@@ -0,0 +1,72 @@
+; RUN: llc < %s | FileCheck %s
+target datalayout = "E-m:e-p:32:32-i128:64-n32"
+target triple = "powerpc-ellcc-linux"
+
+; Function Attrs: nounwind
+define void @foo1(i128* %a, i128* readonly %b, i128* readonly %c) #0 {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %i.02 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %0 = load i128* %b, align 16
+  %1 = load i128* %c, align 16
+  %shl = shl i128 %0, %1
+  store i128 %shl, i128* %a, align 16
+  %inc = add nsw i32 %i.02, 1
+  %exitcond = icmp eq i32 %inc, 2048
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+
+; CHECK-LABEL: @foo1
+; CHECK-NOT: mtctr
+}
+
+; Function Attrs: nounwind
+define void @foo2(i128* %a, i128* readonly %b, i128* readonly %c) #0 {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %i.02 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %0 = load i128* %b, align 16
+  %1 = load i128* %c, align 16
+  %shl = ashr i128 %0, %1
+  store i128 %shl, i128* %a, align 16
+  %inc = add nsw i32 %i.02, 1
+  %exitcond = icmp eq i32 %inc, 2048
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+
+; CHECK-LABEL: @foo2
+; CHECK-NOT: mtctr
+}
+
+; Function Attrs: nounwind
+define void @foo3(i128* %a, i128* readonly %b, i128* readonly %c) #0 {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %i.02 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %0 = load i128* %b, align 16
+  %1 = load i128* %c, align 16
+  %shl = lshr i128 %0, %1
+  store i128 %shl, i128* %a, align 16
+  %inc = add nsw i32 %i.02, 1
+  %exitcond = icmp eq i32 %inc, 2048
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+
+; CHECK-LABEL: @foo3
+; CHECK-NOT: mtctr
+}
+
+attributes #0 = { nounwind }
+