[llvm-commits] [llvm] r50428 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll
Chris Lattner
sabre at nondot.org
Tue Apr 29 10:13:44 PDT 2008
Author: lattner
Date: Tue Apr 29 12:13:43 2008
New Revision: 50428
URL: http://llvm.org/viewvc/llvm-project?rev=50428&view=rev
Log:
fix a subtle volatile handling bug.
Added:
llvm/trunk/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=50428&r1=50427&r2=50428&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Tue Apr 29 12:13:43 2008
@@ -9432,16 +9432,21 @@
// Insert and return the new operation.
if (CastInst* FirstCI = dyn_cast<CastInst>(FirstInst))
return CastInst::create(FirstCI->getOpcode(), PhiVal, PN.getType());
- else if (isa<LoadInst>(FirstInst))
- return new LoadInst(PhiVal, "", isVolatile);
- else if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst))
+ if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst))
return BinaryOperator::create(BinOp->getOpcode(), PhiVal, ConstantOp);
- else if (CmpInst *CIOp = dyn_cast<CmpInst>(FirstInst))
+ if (CmpInst *CIOp = dyn_cast<CmpInst>(FirstInst))
return CmpInst::create(CIOp->getOpcode(), CIOp->getPredicate(),
PhiVal, ConstantOp);
- else
- assert(0 && "Unknown operation");
- return 0;
+ assert(isa<LoadInst>(FirstInst) && "Unknown operation");
+
+ // If this was a volatile load that we are merging, make sure to loop through
+ // and mark all the input loads as non-volatile. If we don't do this, we will
+ // insert a new volatile load and the old ones will not be deletable.
+ if (isVolatile)
+ for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
+ cast<LoadInst>(PN.getIncomingValue(i))->setVolatile(false);
+
+ return new LoadInst(PhiVal, "", isVolatile);
}
/// DeadPHICycle - Return true if this PHI node is only used by a PHI node cycle
Added: llvm/trunk/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll?rev=50428&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2008-04-29-VolatileLoadMerge.ll Tue Apr 29 12:13:43 2008
@@ -0,0 +1,30 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {volatile load} | count 1
+; PR2262
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin8"
+ at g_1 = internal global i32 0 ; <i32*> [#uses=3]
+ at .str = internal constant [13 x i8] c"checksum = 0\00" ; <[13 x i8]*> [#uses=1]
+ at llvm.used = appending global [1 x i8*] [ i8* bitcast (i32 ()* @main to i8*) ], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]
+
+define i32 @main() nounwind {
+entry:
+ %tmp93 = icmp slt i32 0, 10 ; <i1> [#uses=0]
+ %tmp34 = volatile load i32* @g_1, align 4 ; <i32> [#uses=1]
+ br label %bb
+
+bb: ; preds = %bb, %entry
+ %b.0.reg2mem.0 = phi i32 [ 0, %entry ], [ %tmp6, %bb ] ; <i32> [#uses=1]
+ %tmp3.reg2mem.0 = phi i32 [ %tmp34, %entry ], [ %tmp3, %bb ] ; <i32> [#uses=1]
+ %tmp4 = add i32 %tmp3.reg2mem.0, 5 ; <i32> [#uses=1]
+ volatile store i32 %tmp4, i32* @g_1, align 4
+ %tmp6 = add i32 %b.0.reg2mem.0, 1 ; <i32> [#uses=2]
+ %tmp9 = icmp slt i32 %tmp6, 10 ; <i1> [#uses=1]
+ %tmp3 = volatile load i32* @g_1, align 4 ; <i32> [#uses=1]
+ br i1 %tmp9, label %bb, label %bb11
+
+bb11: ; preds = %bb
+ %tmp14 = call i32 @puts( i8* getelementptr ([13 x i8]* @.str, i32 0, i32 0) ) nounwind ; <i32> [#uses=0]
+ ret i32 0
+}
+
+declare i32 @puts(i8*)
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