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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/104912] [12 Regression] 416.gamess regression after r12-7612-g69619acd8d9b58 Date: Mon, 14 Mar 2022 11:55:25 +0000 [thread overview] Message-ID: <bug-104912-4-nivIEcsD5L@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-104912-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104912 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- +mccas.fppized.f:3160:21: optimized: loop vectorized using 16 byte vectors +mccas.fppized.f:3160:21: optimized: loop versioned for vectorization because of possible aliasing +mccas.fppized.f:3195:21: optimized: loop vectorized using 16 byte vectors +mccas.fppized.f:3195:21: optimized: loop versioned for vectorization because of possible aliasing +mccas.fppized.f:3259:21: optimized: loop vectorized using 16 byte vectors +mccas.fppized.f:3259:21: optimized: loop versioned for vectorization because of possible aliasing +mccas.fppized.f:3304:21: optimized: loop vectorized using 16 byte vectors +mccas.fppized.f:3304:21: optimized: loop versioned for vectorization because of possible aliasing mccas.fppized.f:2576:18: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:2524:17: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:3055:22: optimized: loop vectorized using 16 byte vectors @@ -147,9 +155,11 @@ mccas.fppized.f:1890:25: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:1859:20: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:1843:19: optimized: loop vectorized using 16 byte vectors +mccas.fppized.f:1843:19: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:1737:17: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:1727:20: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:1714:19: optimized: loop vectorized using 16 byte vectors +mccas.fppized.f:1714:19: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:884:24: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:904:33: optimized: basic block part vectorized using 16 byte vectors mccas.fppized.f:653:17: optimized: loop vectorized using 16 byte vectors @@ -159,8 +169,11 @@ mccas.fppized.f:1188:14: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:1188:14: optimized: loop versioned for vectorization because of possible aliasing mccas.fppized.f:522:72: optimized: basic block part vectorized using 16 byte vectors +mccas.fppized.f:522:72: optimized: basic block part vectorized using 16 byte vectors mccas.fppized.f:2399:14: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:2399:14: optimized: loop versioned for vectorization because of possible aliasing mccas.fppized.f:2130:14: optimized: loop vectorized using 16 byte vectors mccas.fppized.f:2261:72: optimized: basic block part vectorized using 16 byte vectors +mccas.fppized.f:2261:72: optimized: basic block part vectorized using 16 byte vectors +mccas.fppized.f:2261:72: optimized: basic block part vectorized using 16 byte vectors are the vectorization differences, the performance difference happens entirely in TWOTFF (lines 3209 and following). +mccas.fppized.f:3304:21: optimized: loop vectorized using 16 byte vectors +mccas.fppized.f:3304:21: optimized: loop versioned for vectorization because of possible aliasing are the inner loops of DO 30 MK=1,NOC DO 30 ML=1,MK MKL = MKL+1 XPQKL(MPQ,MKL) = XPQKL(MPQ,MKL) + * VAL1*(CO(MS,MK)*CO(MR,ML)+CO(MS,ML)*CO(MR,MK)) XPQKL(MRS,MKL) = XPQKL(MRS,MKL) + * VAL3*(CO(MQ,MK)*CO(MP,ML)+CO(MQ,ML)*CO(MP,MK)) 30 CONTINUE and the other similar copy. We are doing all strided loads and stores here but the vectorized code never executes, instead we just pay the overhead of the runtime alias test for each inner iteration (we'd ideally formulate it in a way including the outer iteration so we could version the outer loop instead). The runtime alias check is XPOKL(MPQ,MKL) vs. XPOKL(MRS,MKL) - an index check on MPQ should be invariant but I guess the situation is more complicated than that. The cost model differences for this are mccas.fppized.f:3304:21: note: Cost model analysis: Vector inside of loop cost: 552 Vector prologue cost: 48 Vector epilogue cost: 280 Scalar iteration cost: 264 Scalar outside cost: 8 Vector outside cost: 328 prologue iterations: 0 epilogue iterations: 1 mccas.fppized.f:3304:21: missed: cost model: the vector iteration cost = 552 divided by the scalar iteration cost = 264 is greater or equal to the vectorization factor = 2. mccas.fppized.f:3304:21: missed: not vectorized: vectorization not profitable. mccas.fppized.f:3304:21: missed: not vectorized: vector version will never be profitable. mccas.fppized.f:3304:21: missed: Loop costings may not be worthwhile. vs. mccas.fppized.f:3304:21: note: Cost model analysis: Vector inside of loop cost: 480 Vector prologue cost: 48 Vector epilogue cost: 280 Scalar iteration cost: 264 Scalar outside cost: 8 Vector outside cost: 328 prologue iterations: 0 epilogue iterations: 1 Calculated minimum iters for profitability: 4 where the V2DF vec_construct costs are reduced from 24 to 12 which I think is reasonable since we're replacing two scalar loads with one scalar load and one movhpd from memory.
next prev parent reply other threads:[~2022-03-14 11:55 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-14 11:06 [Bug target/104912] New: [12 Regression] 416.gamess regression after r12-7612 rguenth at gcc dot gnu.org 2022-03-14 11:06 ` [Bug target/104912] " rguenth at gcc dot gnu.org 2022-03-14 11:55 ` rguenth at gcc dot gnu.org [this message] 2022-03-14 11:58 ` [Bug target/104912] [12 Regression] 416.gamess regression after r12-7612-g69619acd8d9b58 rguenth at gcc dot gnu.org 2022-03-14 12:17 ` rguenth at gcc dot gnu.org 2022-03-14 13:49 ` rguenth at gcc dot gnu.org 2022-03-14 14:25 ` rguenth at gcc dot gnu.org 2022-03-17 12:31 ` rguenth at gcc dot gnu.org 2022-03-21 13:08 ` rguenth at gcc dot gnu.org 2022-04-13 7:54 ` cvs-commit at gcc dot gnu.org 2022-04-13 8:02 ` rguenth at gcc dot gnu.org 2022-04-20 11:28 ` cvs-commit at gcc dot gnu.org 2022-05-06 8:33 ` [Bug target/104912] [12/13 " jakub at gcc dot gnu.org 2022-07-26 12:42 ` rguenth at gcc dot gnu.org 2023-01-31 11:22 ` jamborm at gcc dot gnu.org 2023-01-31 12:02 ` rguenth at gcc dot gnu.org 2023-05-08 12:24 ` [Bug target/104912] [12/13/14 " rguenth at gcc dot gnu.org
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