Differential D50944
[Hexagon] [Test] Remove undef and infinite loop from test Authored by hermord on Aug 18 2018, 7:16 PM.
Details
As suggested in D50222, this has been refactored into a separate patch. The undef and the infinite loop at the end cause this test to be translated unpredictably. In particular, the checked-for mpy disappears under certain legal optimizations (e.g. the one in D50222). Since the use of these constructs is not relevant to the behavior tested, according to the header comment, this change, suggested by @kparzysz, eliminates them.
Diff Detail
Event TimelineComment Actions After a rebase and bisect, it turned out that the current form does rely on D50222. The extra mpy nodes come from this combine on the srem, which would not be reached with the proposed SREM optimization: Combining: t11: i32 = srem t5, Constant:i32<3> Creating constant: t36: i32 = Constant<1431655766> Creating new node: t37: i32 = mulhs t5, Constant:i32<1431655766> Creating new node: t38: i32 = mul t5, Constant:i32<0> Creating new node: t39: i32 = add t37, t38 Creating constant: t40: i32 = Constant<31> Creating new node: t41: i32 = srl t39, Constant:i32<31> Creating new node: t42: i32 = add t39, t41 Creating new node: t43: i32 = mul t42, Constant:i32<3> Creating new node: t44: i32 = sub t5, t43 ... into: t44: i32 = sub t5, t43 Without the other changes in this patch, the srem was discarded and this did not happen. This change fixes that: though there may be multiple mpys in the loop body, there is only one cmp; looking at it instead still fullfils the purpose of the test (ensuring the loop body is not duplicated), unless I'm mistaken. Comment Actions Yes, I believe so. Tests pass successfully with this and this seems conceputally correct to me,
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It's the multiplication at line 25 that should only occur once. Could you change these two lines to
; CHECK: r{{[0-9]+}} = mpyi ; CHECK-NOT: r{{[0-9]+}} = mpyi