commit 2ff24731bbf905faab6580de7c3e68092ca1ae17
author Hal Finkel <hfinkel@anl.gov> Sat Dec 16 01:26:25 2017 +0000
committer Hal Finkel <hfinkel@anl.gov> Sat Dec 16 01:26:25 2017 +0000
tree b94925a2ab5323a87d297d7e72537838e45fe366
parent 7333aa9f16013bf12e9b1947f636d8a4b4586ef0

[SimplifyLibCalls] Inline calls to cabs when it's safe to do so

When unsafe algerbra is allowed calls to cabs(r) can be replaced by:

  sqrt(creal(r)*creal(r) + cimag(r)*cimag(r))

Patch by Paul Walker, thanks!

Differential Revision: https://reviews.llvm.org/D40069

llvm-svn: 320901

llvm/lib/Analysis/TargetLibraryInfo.cpp

diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index f8facf2..609b996 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -182,6 +182,9 @@
     TLI.setUnavailable(LibFunc_atanh);
     TLI.setUnavailable(LibFunc_atanhf);
     TLI.setUnavailable(LibFunc_atanhl);
+    TLI.setUnavailable(LibFunc_cabs);
+    TLI.setUnavailable(LibFunc_cabsf);
+    TLI.setUnavailable(LibFunc_cabsl);
     TLI.setUnavailable(LibFunc_cbrt);
     TLI.setUnavailable(LibFunc_cbrtf);
     TLI.setUnavailable(LibFunc_cbrtl);
@@ -1267,6 +1270,25 @@
     return (NumParams == 1 && FTy.getParamType(0)->isPointerTy() &&
             FTy.getReturnType()->isIntegerTy());
 
+  case LibFunc_cabs:
+  case LibFunc_cabsf:
+  case LibFunc_cabsl: {
+    Type* RetTy = FTy.getReturnType();
+    if (!RetTy->isFloatingPointTy())
+      return false;
+
+    // NOTE: These prototypes are target specific and currently support
+    // "complex" passed as an array or discrete real & imaginary parameters.
+    // Add other calling conventions to enable libcall optimizations.
+    if (NumParams == 1)
+      return (FTy.getParamType(0)->isArrayTy() &&
+              FTy.getParamType(0)->getArrayNumElements() == 2 &&
+              FTy.getParamType(0)->getArrayElementType() == RetTy);
+    else if (NumParams == 2)
+      return (FTy.getParamType(0) == RetTy && FTy.getParamType(1) == RetTy);
+    else
+      return false;
+  }
   case LibFunc::NumLibFuncs:
     break;
   }