[llvm] r188727 - Don't form PPC CTR-based loops around a copysignl call

[Hal Finkel]

Author: hfinkel
Date: Mon Aug 19 18:35:24 2013
New Revision: 188727

URL: http://llvm.org/viewvc/llvm-project?rev=188727&view=rev
Log:
Don't form PPC CTR-based loops around a copysignl call

copysign/copysignf never become function calls (because the SDAG expansion code
does not lower to the corresponding function call, but rather directly
implements the associated logic), but copysignl almost always is lowered into a
call to the requested libm functon (and, thus, might clobber CTR).

Added:
    llvm/trunk/test/CodeGen/PowerPC/ctrloop-cpsgn.ll
Modified:
    llvm/trunk/lib/Target/PowerPC/PPCCTRLoops.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCCTRLoops.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCCTRLoops.cpp?rev=188727&r1=188726&r2=188727&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCCTRLoops.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCCTRLoops.cpp Mon Aug 19 18:35:24 2013
@@ -284,8 +284,9 @@ bool PPCCTRLoops::mightUseCTR(const Trip
           default: return true;
           case LibFunc::copysign:
           case LibFunc::copysignf:
-          case LibFunc::copysignl:
             continue; // ISD::FCOPYSIGN is never a library call.
+          case LibFunc::copysignl:
+            return true;
           case LibFunc::fabs:
           case LibFunc::fabsf:
           case LibFunc::fabsl:

Added: llvm/trunk/test/CodeGen/PowerPC/ctrloop-cpsgn.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/ctrloop-cpsgn.ll?rev=188727&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/ctrloop-cpsgn.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/ctrloop-cpsgn.ll Mon Aug 19 18:35:24 2013
@@ -0,0 +1,28 @@
+; RUN: llc < %s -mcpu=ppc | FileCheck %s
+
+target datalayout = "E-p:32:32:32-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"
+target triple = "powerpc-unknown-linux-gnu"
+
+define ppc_fp128 @foo(ppc_fp128* nocapture %n, ppc_fp128 %d) nounwind readonly {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %i.06 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  %x.05 = phi ppc_fp128 [ %d, %entry ], [ %conv, %for.body ]
+  %arrayidx = getelementptr inbounds ppc_fp128* %n, i32 %i.06
+  %0 = load ppc_fp128* %arrayidx, align 8
+  %conv = tail call ppc_fp128 @copysignl(ppc_fp128 %x.05, ppc_fp128 %d) nounwind readonly
+  %inc = add nsw i32 %i.06, 1
+  %exitcond = icmp eq i32 %inc, 2048
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret ppc_fp128 %conv
+}
+
+declare ppc_fp128 @copysignl(ppc_fp128, ppc_fp128) #0
+
+; CHECK: @foo
+; CHECK-NOT: mtctr
+