[llvm-commits] [llvm] r171583 - in /llvm/trunk: lib/Transforms/Vectorize/LoopVectorize.cpp test/Transforms/LoopVectorize/gcc-examples.ll test/Transforms/LoopVectorize/reduction.ll
Nadav Rotem
nrotem at apple.com
Fri Jan 4 17:15:47 PST 2013
Author: nadav
Date: Fri Jan 4 19:15:47 2013
New Revision: 171583
URL: http://llvm.org/viewvc/llvm-project?rev=171583&view=rev
Log:
iLoopVectorize: Non commutative operators can be used as reduction variables as long as the reduction chain is used in the LHS.
PR14803.
Modified:
llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
llvm/trunk/test/Transforms/LoopVectorize/gcc-examples.ll
llvm/trunk/test/Transforms/LoopVectorize/reduction.ll
Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=171583&r1=171582&r2=171583&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Fri Jan 4 19:15:47 2013
@@ -1912,10 +1912,6 @@
if (Iter->use_empty())
return false;
- // Any reduction instr must be of one of the allowed kinds.
- if (!isReductionInstr(Iter, Kind))
- return false;
-
// Did we find a user inside this loop already ?
bool FoundInBlockUser = false;
// Did we reach the initial PHI node already ?
@@ -1953,6 +1949,16 @@
if (FoundInBlockUser)
return false;
FoundInBlockUser = true;
+
+ // Any reduction instr must be of one of the allowed kinds.
+ if (!isReductionInstr(U, Kind))
+ return false;
+
+ // Reductions of instructions such as Div, and Sub is only
+ // possible if the LHS is the reduction variable.
+ if (!U->isCommutative() && U->getOperand(0) != Iter)
+ return false;
+
Iter = U;
}
@@ -1985,8 +1991,11 @@
case Instruction::PHI:
// possibly.
return true;
+ case Instruction::Sub:
case Instruction::Add:
return Kind == IntegerAdd;
+ case Instruction::SDiv:
+ case Instruction::UDiv:
case Instruction::Mul:
return Kind == IntegerMult;
case Instruction::And:
Modified: llvm/trunk/test/Transforms/LoopVectorize/gcc-examples.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/gcc-examples.ll?rev=171583&r1=171582&r2=171583&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/gcc-examples.ll (original)
+++ llvm/trunk/test/Transforms/LoopVectorize/gcc-examples.ll Fri Jan 4 19:15:47 2013
@@ -241,7 +241,7 @@
}
;CHECK: @example9
-;CHECK-NOT: phi <4 x i32>
+;CHECK: phi <4 x i32>
;CHECK: ret i32
define i32 @example9() nounwind uwtable readonly ssp {
br label %1
Modified: llvm/trunk/test/Transforms/LoopVectorize/reduction.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/reduction.ll?rev=171583&r1=171582&r2=171583&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/reduction.ll (original)
+++ llvm/trunk/test/Transforms/LoopVectorize/reduction.ll Fri Jan 4 19:15:47 2013
@@ -296,11 +296,12 @@
ret i32 %x.0.lcssa
}
-;CHECK: @reduction_sub_lhs
+; In this code the subtracted variable is on the RHS and this is not an induction variable.
+;CHECK: @reduction_sub_rhs
;CHECK-NOT: phi <4 x i32>
;CHECK-NOT: sub nsw <4 x i32>
;CHECK: ret i32
-define i32 @reduction_sub_lhs(i32 %n, i32* noalias nocapture %A) nounwind uwtable readonly {
+define i32 @reduction_sub_rhs(i32 %n, i32* noalias nocapture %A) nounwind uwtable readonly {
entry:
%cmp4 = icmp sgt i32 %n, 0
br i1 %cmp4, label %for.body, label %for.end
@@ -320,3 +321,30 @@
%x.0.lcssa = phi i32 [ 0, %entry ], [ %sub, %for.body ]
ret i32 %x.0.lcssa
}
+
+
+; In this test the reduction variable is on the LHS and we can vectorize it.
+;CHECK: @reduction_sub_lhs
+;CHECK: phi <4 x i32>
+;CHECK: sub nsw <4 x i32>
+;CHECK: ret i32
+define i32 @reduction_sub_lhs(i32 %n, i32* noalias nocapture %A) nounwind uwtable readonly {
+entry:
+ %cmp4 = icmp sgt i32 %n, 0
+ br i1 %cmp4, label %for.body, label %for.end
+
+for.body: ; preds = %entry, %for.body
+ %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
+ %x.05 = phi i32 [ %sub, %for.body ], [ 0, %entry ]
+ %arrayidx = getelementptr inbounds i32* %A, i64 %indvars.iv
+ %0 = load i32* %arrayidx, align 4
+ %sub = sub nsw i32 %x.05, %0
+ %indvars.iv.next = add i64 %indvars.iv, 1
+ %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+ %exitcond = icmp eq i32 %lftr.wideiv, %n
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body, %entry
+ %x.0.lcssa = phi i32 [ 0, %entry ], [ %sub, %for.body ]
+ ret i32 %x.0.lcssa
+}
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