[all-commits] [llvm/llvm-project] 930996: [ValueTracking][NFC] Pass `SimplifyQuery` to `comp...

[Yingwei Zheng via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 930996e9e442d69a321cd5c945543d37c97f4c0e
      https://github.com/llvm/llvm-project/commit/930996e9e442d69a321cd5c945543d37c97f4c0e
  Author: Yingwei Zheng <dtcxzyw2333 at gmail.com>
  Date:   2024-02-06 (Tue, 06 Feb 2024)

  Changed paths:
    M llvm/include/llvm/Analysis/ValueTracking.h
    M llvm/lib/Analysis/InstructionSimplify.cpp
    M llvm/lib/Analysis/ValueTracking.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUInstCombineIntrinsic.cpp
    M llvm/lib/Target/AMDGPU/AMDGPULibCalls.cpp
    M llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp
    M llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
    M llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
    M llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
    M llvm/lib/Transforms/InstCombine/InstCombineInternal.h
    M llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
    M llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp

  Log Message:
  -----------
  [ValueTracking][NFC] Pass `SimplifyQuery` to `computeKnownFPClass` family (#80657)

This patch refactors the interface of the `computeKnownFPClass` family
to pass `SimplifyQuery` directly.
The motivation of this patch is to compute known fpclass with
`DomConditionCache`, which was introduced by
https://github.com/llvm/llvm-project/pull/73662. With
`DomConditionCache`, we can do more optimization with context-sensitive
information.

Example (extracted from
[fmt/format.h](https://github.com/fmtlib/fmt/blob/e17bc67547a66cdd378ca6a90c56b865d30d6168/include/fmt/format.h#L3555-L3566)):
```
define float @test(float %x, i1 %cond) {
  %i32 = bitcast float %x to i32
  %cmp = icmp slt i32 %i32, 0
  br i1 %cmp, label %if.then1, label %if.else

if.then1:
  %fneg = fneg float %x
  br label %if.end

if.else:
  br i1 %cond, label %if.then2, label %if.end

if.then2:
  br label %if.end

if.end:
  %value = phi float [ %fneg, %if.then1 ], [ %x, %if.then2 ], [ %x, %if.else ]
  %ret = call float @llvm.fabs.f32(float %value)
  ret float %ret
}
```
We can prove the signbit of `%value` is always zero. Then the fabs can
be eliminated.