Sanjay Patel 750f4c591d [InstCombine] allow peeking through zext of shift amount to match rotate idioms (PR45701) ...

We might want to also allow trunc of the shift amount, but that seems less likely?

  define i32 @src(i32 %x, i1 %y) {
  %0:
    %rem = and i1 %y, 1
    %cmp = icmp eq i1 %rem, 0
    %sh_prom = zext i1 %rem to i32
    %sub = sub nsw nuw i1 0, %rem
    %sh_prom1 = zext i1 %sub to i32
    %shr = lshr i32 %x, %sh_prom1
    %shl = shl i32 %x, %sh_prom
    %or = or i32 %shl, %shr
    %r = select i1 %cmp, i32 %x, i32 %or
    ret i32 %r
  }
  =>
  define i32 @tgt(i32 %x, i1 %y) {
  %0:
    %t = zext i1 %y to i32
    %r = fshl i32 %x, i32 %x, i32 %t
    ret i32 %r
  }

  Transformation seems to be correct!

https://alive2.llvm.org/ce/z/xgMvE3

http://bugs.llvm.org/PR45701

2020-07-20 16:18:11 -04:00

..

CMakeLists.txt

[InstCombine] Negator - sink sinkable negations

2020-04-21 22:00:23 +03:00

InstCombineAddSub.cpp

[InstCombine] reassociate diff of sums into sum of diffs

2020-06-22 20:47:09 -04:00

InstCombineAndOrXor.cpp

[InstCombine] prevent infinite looping in or-icmp fold (PR46712)

2020-07-15 14:12:12 -04:00

InstCombineAtomicRMW.cpp

[NFC] Modernize misc. uses of Align/MaybeAlign APIs.

2020-04-06 17:53:04 -07:00

InstCombineCalls.cpp

Temporarily Revert "[AssumeBundles] Use operand bundles to encode alignment assumptions"

2020-07-16 11:54:04 -07:00

InstCombineCasts.cpp

[InstCombine] Try to narrow expr if trunc cannot be removed.

2020-07-03 20:22:51 +01:00

InstCombineCompares.cpp

[InstCombine] fix miscompile from umul_with_overflow matching

2020-07-04 11:16:23 -04:00

InstCombineInternal.h

[InstCombine] Fix store merge worklist management (PR46680)

2020-07-19 15:05:45 +02:00

InstCombineLoadStoreAlloca.cpp

[NFCI][InstCombine] Move store merging from visitStoreInst() into visitUnconditionalBranchInst()

2020-07-14 10:41:51 +03:00

InstCombineMulDivRem.cpp

[InstCombine] Fold X sdiv (-1 << C) -> -(X u>> Y) iff X is non-negative

2020-07-17 22:50:09 +03:00

InstCombineNegator.cpp

[InstCombine] Negator: while there, add detection for cycles during negation

2020-06-17 22:47:20 +03:00

InstCombinePHI.cpp

Re-enable "[InstCombine] Simplify boolean Phis with const inputs using CFG"

2020-07-16 16:09:08 +07:00

InstCombineSelect.cpp

[InstCombine] allow peeking through zext of shift amount to match rotate idioms (PR45701)

2020-07-20 16:18:11 -04:00

InstCombineShifts.cpp

[SVE] Update API ConstantVector::getSplat() to use ElementCount.

2020-03-12 13:22:41 -07:00

InstCombineSimplifyDemanded.cpp

Add intrinsic helper function

2020-06-29 14:47:46 +02:00

InstCombineTables.td

…

InstCombineVectorOps.cpp

[SVE] Eliminate calls to default-false VectorType::get() from InstCombine

2020-05-29 15:31:31 -07:00

InstructionCombining.cpp

Reland "[InstCombine] Lower infinite combine loop detection thresholds"

2020-07-19 16:37:03 +03:00

LLVMBuild.txt

…