[llvm-commits] [llvm] r160894 - in /llvm/trunk: lib/Transforms/Scalar/CodeGenPrepare.cpp lib/Transforms/Utils/BasicBlockUtils.cpp test/CodeGen/X86/tailcall-cgp-dup.ll
Evan Cheng
evan.cheng at apple.com
Fri Jul 27 14:21:26 PDT 2012
Author: evancheng
Date: Fri Jul 27 16:21:26 2012
New Revision: 160894
URL: http://llvm.org/viewvc/llvm-project?rev=160894&view=rev
Log:
Teach CodeGenPrep to look past bitcast when it's duplicating return instruction
into predecessor blocks to enable tail call optimization.
rdar://11958338
Added:
llvm/trunk/test/CodeGen/X86/tailcall-cgp-dup.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp
llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp?rev=160894&r1=160893&r2=160894&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp Fri Jul 27 16:21:26 2012
@@ -645,10 +645,18 @@
if (!TLI)
return false;
+ PHINode *PN = 0;
+ BitCastInst *BCI = 0;
Value *V = RI->getReturnValue();
- PHINode *PN = V ? dyn_cast<PHINode>(V) : NULL;
- if (V && !PN)
- return false;
+ if (V) {
+ BCI = dyn_cast<BitCastInst>(V);
+ if (BCI)
+ V = BCI->getOperand(0);
+
+ PN = dyn_cast<PHINode>(V);
+ if (!PN)
+ return false;
+ }
BasicBlock *BB = RI->getParent();
if (PN && PN->getParent() != BB)
@@ -666,6 +674,9 @@
if (PN) {
BasicBlock::iterator BI = BB->begin();
do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
+ if (&*BI == BCI)
+ // Also skip over the bitcast.
+ ++BI;
if (&*BI != RI)
return false;
} else {
Modified: llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp?rev=160894&r1=160893&r2=160894&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/BasicBlockUtils.cpp Fri Jul 27 16:21:26 2012
@@ -659,10 +659,26 @@
// If the return instruction returns a value, and if the value was a
// PHI node in "BB", propagate the right value into the return.
for (User::op_iterator i = NewRet->op_begin(), e = NewRet->op_end();
- i != e; ++i)
- if (PHINode *PN = dyn_cast<PHINode>(*i))
- if (PN->getParent() == BB)
- *i = PN->getIncomingValueForBlock(Pred);
+ i != e; ++i) {
+ Value *V = *i;
+ Instruction *NewBC = 0;
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V)) {
+ // Return value might be bitcasted. Clone and insert it before the
+ // return instruction.
+ V = BCI->getOperand(0);
+ NewBC = BCI->clone();
+ Pred->getInstList().insert(NewRet, NewBC);
+ *i = NewBC;
+ }
+ if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ if (PN->getParent() == BB) {
+ if (NewBC)
+ NewBC->setOperand(0, PN->getIncomingValueForBlock(Pred));
+ else
+ *i = PN->getIncomingValueForBlock(Pred);
+ }
+ }
+ }
// Update any PHI nodes in the returning block to realize that we no
// longer branch to them.
Added: llvm/trunk/test/CodeGen/X86/tailcall-cgp-dup.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/tailcall-cgp-dup.ll?rev=160894&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/tailcall-cgp-dup.ll (added)
+++ llvm/trunk/test/CodeGen/X86/tailcall-cgp-dup.ll Fri Jul 27 16:21:26 2012
@@ -0,0 +1,87 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+
+; Teach CGP to dup returns to enable tail call optimization.
+; rdar://9147433
+
+define i32 @foo(i32 %x) nounwind ssp {
+; CHECK: foo:
+entry:
+ switch i32 %x, label %return [
+ i32 1, label %sw.bb
+ i32 2, label %sw.bb1
+ i32 3, label %sw.bb3
+ i32 4, label %sw.bb5
+ i32 5, label %sw.bb7
+ i32 6, label %sw.bb9
+ ]
+
+sw.bb: ; preds = %entry
+; CHECK: jmp _f1
+ %call = tail call i32 @f1() nounwind
+ br label %return
+
+sw.bb1: ; preds = %entry
+; CHECK: jmp _f2
+ %call2 = tail call i32 @f2() nounwind
+ br label %return
+
+sw.bb3: ; preds = %entry
+; CHECK: jmp _f3
+ %call4 = tail call i32 @f3() nounwind
+ br label %return
+
+sw.bb5: ; preds = %entry
+; CHECK: jmp _f4
+ %call6 = tail call i32 @f4() nounwind
+ br label %return
+
+sw.bb7: ; preds = %entry
+; CHECK: jmp _f5
+ %call8 = tail call i32 @f5() nounwind
+ br label %return
+
+sw.bb9: ; preds = %entry
+; CHECK: jmp _f6
+ %call10 = tail call i32 @f6() nounwind
+ br label %return
+
+return: ; preds = %entry, %sw.bb9, %sw.bb7, %sw.bb5, %sw.bb3, %sw.bb1, %sw.bb
+ %retval.0 = phi i32 [ %call10, %sw.bb9 ], [ %call8, %sw.bb7 ], [ %call6, %sw.bb5 ], [ %call4, %sw.bb3 ], [ %call2, %sw.bb1 ], [ %call, %sw.bb ], [ 0, %entry ]
+ ret i32 %retval.0
+}
+
+declare i32 @f1()
+
+declare i32 @f2()
+
+declare i32 @f3()
+
+declare i32 @f4()
+
+declare i32 @f5()
+
+declare i32 @f6()
+
+; rdar://11958338
+%0 = type opaque
+
+declare i8* @bar(i8*) uwtable optsize noinline ssp
+
+define hidden %0* @thingWithValue(i8* %self) uwtable ssp {
+entry:
+; CHECK: thingWithValue:
+; CHECK: jmp _bar
+ br i1 undef, label %if.then.i, label %if.else.i
+
+if.then.i: ; preds = %entry
+ br label %someThingWithValue.exit
+
+if.else.i: ; preds = %entry
+ %call4.i = tail call i8* @bar(i8* undef) optsize
+ br label %someThingWithValue.exit
+
+someThingWithValue.exit: ; preds = %if.else.i, %if.then.i
+ %retval.0.in.i = phi i8* [ undef, %if.then.i ], [ %call4.i, %if.else.i ]
+ %retval.0.i = bitcast i8* %retval.0.in.i to %0*
+ ret %0* %retval.0.i
+}
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