[llvm-branch-commits] [llvm-branch] r197453 - Merging r197449:
Bill Wendling
isanbard at gmail.com
Mon Dec 16 17:28:36 PST 2013
Author: void
Date: Mon Dec 16 19:28:35 2013
New Revision: 197453
URL: http://llvm.org/viewvc/llvm-project?rev=197453&view=rev
Log:
Merging r197449:
------------------------------------------------------------------------
r197449 | arnolds | 2013-12-16 17:11:01 -0800 (Mon, 16 Dec 2013) | 7 lines
LoopVectorizer: Don't if-convert constant expressions that can trap
A phi node operand or an instruction operand could be a constant expression that
can trap (division). Check that we don't vectorize such cases.
PR16729
radar://15653590
------------------------------------------------------------------------
Modified:
llvm/branches/release_34/ (props changed)
llvm/branches/release_34/lib/Transforms/Vectorize/LoopVectorize.cpp
llvm/branches/release_34/test/Transforms/LoopVectorize/if-conversion.ll
Propchange: llvm/branches/release_34/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Mon Dec 16 19:28:35 2013
@@ -1,3 +1,3 @@
/llvm/branches/Apple/Pertwee:110850,110961
/llvm/branches/type-system-rewrite:133420-134817
-/llvm/trunk:155241,195092-195094,195100,195102-195103,195118,195129,195136,195138,195148,195152,195156-195157,195161-195162,195193,195272,195317-195318,195327,195330,195333,195339,195343,195355,195364,195379,195397-195399,195401,195408,195411,195421,195423-195424,195432,195439,195444,195455-195456,195469,195476-195477,195479,195491-195495,195504-195505,195514,195528,195535,195547,195567,195573-195576,195590-195591,195599,195632,195635-195636,195670,195677,195679,195682,195684,195710,195713,195716,195769,195773,195779,195782,195787-195788,195791,195803,195812,195827,195834,195843-195844,195878-195881,195887,195903,195905,195912,195915,195932,195936-195943,195972-195973,195975-195976,196004,196044-196046,196069,196100,196104,196129,196144,196151,196153,196156,196158,196172,196189-196192,196198-196199,196208-196211,196261,196267,196269,196294,196359-196362,196369,196391,196456,196493,196508,196532-196533,196535,196538,196588,196611-196612,196637-196638,196658,196668,196725,196!
735,19675
1,196755,196768,196806,196858,197047,197089,197178,197215-197216,197228
+/llvm/trunk:155241,195092-195094,195100,195102-195103,195118,195129,195136,195138,195148,195152,195156-195157,195161-195162,195193,195272,195317-195318,195327,195330,195333,195339,195343,195355,195364,195379,195397-195399,195401,195408,195411,195421,195423-195424,195432,195439,195444,195455-195456,195469,195476-195477,195479,195491-195495,195504-195505,195514,195528,195535,195547,195567,195573-195576,195590-195591,195599,195632,195635-195636,195670,195677,195679,195682,195684,195710,195713,195716,195769,195773,195779,195782,195787-195788,195791,195803,195812,195827,195834,195843-195844,195878-195881,195887,195903,195905,195912,195915,195932,195936-195943,195972-195973,195975-195976,196004,196044-196046,196069,196100,196104,196129,196144,196151,196153,196156,196158,196172,196189-196192,196198-196199,196208-196211,196261,196267,196269,196294,196359-196362,196369,196391,196456,196493,196508,196532-196533,196535,196538,196588,196611-196612,196637-196638,196658,196668,196725,196!
735,19675
1,196755,196768,196806,196858,197047,197089,197178,197215-197216,197228,197449
Modified: llvm/branches/release_34/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=197453&r1=197452&r2=197453&view=diff
==============================================================================
--- llvm/branches/release_34/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/branches/release_34/lib/Transforms/Vectorize/LoopVectorize.cpp Mon Dec 16 19:28:35 2013
@@ -2781,6 +2781,23 @@ void InnerLoopVectorizer::updateAnalysis
DEBUG(DT->verifyAnalysis());
}
+/// \brief Check whether it is safe to if-convert this phi node.
+///
+/// Phi nodes with constant expressions that can trap are not safe to if
+/// convert.
+static bool canIfConvertPHINodes(BasicBlock *BB) {
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
+ PHINode *Phi = dyn_cast<PHINode>(I);
+ if (!Phi)
+ return true;
+ for (unsigned p = 0, e = Phi->getNumIncomingValues(); p != e; ++p)
+ if (Constant *C = dyn_cast<Constant>(Phi->getIncomingValue(p)))
+ if (C->canTrap())
+ return false;
+ }
+ return true;
+}
+
bool LoopVectorizationLegality::canVectorizeWithIfConvert() {
if (!EnableIfConversion)
return false;
@@ -2807,6 +2824,7 @@ bool LoopVectorizationLegality::canVecto
}
// Collect the blocks that need predication.
+ BasicBlock *Header = TheLoop->getHeader();
for (Loop::block_iterator BI = TheLoop->block_begin(),
BE = TheLoop->block_end(); BI != BE; ++BI) {
BasicBlock *BB = *BI;
@@ -2816,8 +2834,12 @@ bool LoopVectorizationLegality::canVecto
return false;
// We must be able to predicate all blocks that need to be predicated.
- if (blockNeedsPredication(BB) && !blockCanBePredicated(BB, SafePointes))
+ if (blockNeedsPredication(BB)) {
+ if (!blockCanBePredicated(BB, SafePointes))
+ return false;
+ } else if (BB != Header && !canIfConvertPHINodes(BB))
return false;
+
}
// We can if-convert this loop.
@@ -4371,6 +4393,14 @@ bool LoopVectorizationLegality::blockCan
if (it->mayWriteToMemory() || it->mayThrow())
return false;
+ // Check that we don't have a constant expression that can trap as operand.
+ for (Instruction::op_iterator OI = it->op_begin(), OE = it->op_end();
+ OI != OE; ++OI) {
+ if (Constant *C = dyn_cast<Constant>(*OI))
+ if (C->canTrap())
+ return false;
+ }
+
// The instructions below can trap.
switch (it->getOpcode()) {
default: continue;
Modified: llvm/branches/release_34/test/Transforms/LoopVectorize/if-conversion.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/Transforms/LoopVectorize/if-conversion.ll?rev=197453&r1=197452&r2=197453&view=diff
==============================================================================
--- llvm/branches/release_34/test/Transforms/LoopVectorize/if-conversion.ll (original)
+++ llvm/branches/release_34/test/Transforms/LoopVectorize/if-conversion.ll Mon Dec 16 19:28:35 2013
@@ -106,3 +106,66 @@ for.end:
ret i32 %sum.0.lcssa
}
+ at a = common global [1 x i32*] zeroinitializer, align 8
+ at c = common global i32* null, align 8
+
+; We use to if convert this loop. This is not safe because there is a trapping
+; constant expression.
+; PR16729
+
+; CHECK-LABEL: trapping_constant_expression
+; CHECK-NOT: or <4 x i32>
+
+define i32 @trapping_constant_expression() {
+entry:
+ br label %for.body
+
+for.body:
+ %inc3 = phi i32 [ 0, %entry ], [ %inc, %cond.end ]
+ %or2 = phi i32 [ 0, %entry ], [ %or, %cond.end ]
+ br i1 icmp eq (i32** getelementptr inbounds ([1 x i32*]* @a, i64 0, i64 0), i32** @c), label %cond.false, label %cond.end
+
+cond.false:
+ br label %cond.end
+
+cond.end:
+ %cond = phi i32 [ sdiv (i32 1, i32 zext (i1 icmp eq (i32** getelementptr inbounds ([1 x i32*]* @a, i64 0, i64 0), i32** @c) to i32)), %cond.false ], [ 0, %for.body ]
+ %or = or i32 %or2, %cond
+ %inc = add nsw i32 %inc3, 1
+ %cmp = icmp slt i32 %inc, 128
+ br i1 %cmp, label %for.body, label %for.end
+
+for.end:
+ ret i32 %or
+}
+
+; Neither should we if-convert if there is an instruction operand that is a
+; trapping constant expression.
+; PR16729
+
+; CHECK-LABEL: trapping_constant_expression2
+; CHECK-NOT: or <4 x i32>
+
+define i32 @trapping_constant_expression2() {
+entry:
+ br label %for.body
+
+for.body:
+ %inc3 = phi i32 [ 0, %entry ], [ %inc, %cond.end ]
+ %or2 = phi i32 [ 0, %entry ], [ %or, %cond.end ]
+ br i1 icmp eq (i32** getelementptr inbounds ([1 x i32*]* @a, i64 0, i64 0), i32** @c), label %cond.false, label %cond.end
+
+cond.false:
+ %cond.1 = or i32 %inc3, sdiv (i32 1, i32 zext (i1 icmp eq (i32** getelementptr inbounds ([1 x i32*]* @a, i64 0, i64 0), i32** @c) to i32))
+ br label %cond.end
+
+cond.end:
+ %cond = phi i32 [ %cond.1, %cond.false ], [ %inc3, %for.body ]
+ %or = or i32 %or2, %cond
+ %inc = add nsw i32 %inc3, 1
+ %cmp = icmp slt i32 %inc, 128
+ br i1 %cmp, label %for.body, label %for.end
+
+for.end:
+ ret i32 %or
+}
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