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| author | Craig Topper <craig.topper@intel.com> | 2018-05-03 05:48:49 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2018-05-03 05:48:49 +0000 |
| commit | 856fd686908aac7edb37f1013874cb79c84de5bc (patch) | |
| tree | 1c1e08c22c2e6ad5456d83bbf2caa837f0e74c3f | |
| parent | a0cba89f861da4cba80c28a1d3cf30c8e0fb436e (diff) | |
| download | bcm5719-llvm-856fd686908aac7edb37f1013874cb79c84de5bc.tar.gz bcm5719-llvm-856fd686908aac7edb37f1013874cb79c84de5bc.zip | |
[LoopIdiomRecognize] When looking for 'x & (x -1)' for popcnt, make sure the left hand side of the 'and' matches the left hand side of the 'subtract'
llvm-svn: 331437
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp | 2 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopIdiom/X86/popcnt.ll | 16 |
2 files changed, 7 insertions, 11 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp index fc64058fd4a..59753579bc3 100644 --- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp +++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp @@ -1196,7 +1196,7 @@ static bool detectPopcountIdiom(Loop *CurLoop, BasicBlock *PreCondBB, VarX1 = DefX2->getOperand(0); SubOneOp = dyn_cast<BinaryOperator>(DefX2->getOperand(1)); } - if (!SubOneOp) + if (!SubOneOp || SubOneOp->getOperand(0) != VarX1) return false; ConstantInt *Dec = dyn_cast<ConstantInt>(SubOneOp->getOperand(1)); diff --git a/llvm/test/Transforms/LoopIdiom/X86/popcnt.ll b/llvm/test/Transforms/LoopIdiom/X86/popcnt.ll index 94e836b7440..4c8920358d6 100644 --- a/llvm/test/Transforms/LoopIdiom/X86/popcnt.ll +++ b/llvm/test/Transforms/LoopIdiom/X86/popcnt.ll @@ -139,29 +139,25 @@ while.end: ; preds = %while.body, %entry ret i32 %c.0.lcssa } -; The a & (a - 1) in the loop is a & (b - 1) in this code. -; FIXME: We shouldn't emit ctpop for this. +; The a & (a - 1) in the loop is a & (b - 1) in this code. Make sure we don't +; convert it. define i32 @popcount_bad(i64 %a, i64 %b) nounwind uwtable readnone ssp { ; CHECK-LABEL: @popcount_bad( ; CHECK-NEXT: entry: -; CHECK-NEXT: [[TMP0:%.*]] = call i64 @llvm.ctpop.i64(i64 [[A:%.*]]) -; CHECK-NEXT: [[TMP1:%.*]] = trunc i64 [[TMP0]] to i32 -; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i32 [[TMP1]], 0 -; CHECK-NEXT: br i1 [[TMP2]], label [[WHILE_END:%.*]], label [[WHILE_BODY_PREHEADER:%.*]] +; CHECK-NEXT: [[TOBOOL3:%.*]] = icmp eq i64 [[A:%.*]], 0 +; CHECK-NEXT: br i1 [[TOBOOL3]], label [[WHILE_END:%.*]], label [[WHILE_BODY_PREHEADER:%.*]] ; CHECK: while.body.preheader: ; CHECK-NEXT: br label [[WHILE_BODY:%.*]] ; CHECK: while.body: -; CHECK-NEXT: [[TCPHI:%.*]] = phi i32 [ [[TMP1]], [[WHILE_BODY_PREHEADER]] ], [ [[TCDEC:%.*]], [[WHILE_BODY]] ] ; CHECK-NEXT: [[C_05:%.*]] = phi i32 [ [[INC:%.*]], [[WHILE_BODY]] ], [ 0, [[WHILE_BODY_PREHEADER]] ] ; CHECK-NEXT: [[A_ADDR_04:%.*]] = phi i64 [ [[AND:%.*]], [[WHILE_BODY]] ], [ [[A]], [[WHILE_BODY_PREHEADER]] ] ; CHECK-NEXT: [[INC]] = add nsw i32 [[C_05]], 1 ; CHECK-NEXT: [[SUB:%.*]] = add i64 [[B:%.*]], -1 ; CHECK-NEXT: [[AND]] = and i64 [[SUB]], [[A_ADDR_04]] -; CHECK-NEXT: [[TCDEC]] = sub nsw i32 [[TCPHI]], 1 -; CHECK-NEXT: [[TOBOOL:%.*]] = icmp sle i32 [[TCDEC]], 0 +; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i64 [[AND]], 0 ; CHECK-NEXT: br i1 [[TOBOOL]], label [[WHILE_END_LOOPEXIT:%.*]], label [[WHILE_BODY]] ; CHECK: while.end.loopexit: -; CHECK-NEXT: [[INC_LCSSA:%.*]] = phi i32 [ [[TMP1]], [[WHILE_BODY]] ] +; CHECK-NEXT: [[INC_LCSSA:%.*]] = phi i32 [ [[INC]], [[WHILE_BODY]] ] ; CHECK-NEXT: br label [[WHILE_END]] ; CHECK: while.end: ; CHECK-NEXT: [[C_0_LCSSA:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC_LCSSA]], [[WHILE_END_LOOPEXIT]] ] |
