[PATCH] R600: Implement TTI:getPopcntSupport

[Tom Stellard]

On Thu, Jul 17, 2014 at 06:45:48PM +0000, Matt Arsenault wrote:
> The test is just copied from X86, and I don't know of a better way to test it.
> 

LGTM.

> http://reviews.llvm.org/D4569
> 
> Files:
>   lib/Target/R600/AMDGPUSubtarget.h
>   lib/Target/R600/AMDGPUTargetTransformInfo.cpp
>   test/Transforms/LoopIdiom/R600/lit.local.cfg
>   test/Transforms/LoopIdiom/R600/popcnt.ll

> Index: lib/Target/R600/AMDGPUSubtarget.h
> ===================================================================
> --- lib/Target/R600/AMDGPUSubtarget.h
> +++ lib/Target/R600/AMDGPUSubtarget.h
> @@ -123,8 +123,10 @@
>      if (Size == 32)
>        return (getGeneration() >= EVERGREEN);
>  
> -    assert(Size == 64);
> -    return (getGeneration() >= SOUTHERN_ISLANDS);
> +    if (Size == 64)
> +      return (getGeneration() >= SOUTHERN_ISLANDS);
> +
> +    return false;
>    }
>  
>    bool hasMulU24() const {
> Index: lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> ===================================================================
> --- lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> +++ lib/Target/R600/AMDGPUTargetTransformInfo.cpp
> @@ -77,6 +77,8 @@
>    void getUnrollingPreferences(Loop *L,
>                                 UnrollingPreferences &UP) const override;
>  
> +  PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) const override;
> +
>    /// @}
>  };
>  
> @@ -119,3 +121,9 @@
>      }
>    }
>  }
> +
> +AMDGPUTTI::PopcntSupportKind
> +AMDGPUTTI::getPopcntSupport(unsigned TyWidth) const {
> +  assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
> +  return ST->hasBCNT(TyWidth) ? PSK_FastHardware : PSK_Software;
> +}
> Index: test/Transforms/LoopIdiom/R600/lit.local.cfg
> ===================================================================
> --- /dev/null
> +++ test/Transforms/LoopIdiom/R600/lit.local.cfg
> @@ -0,0 +1,3 @@
> +if not 'R600' in config.root.targets:
> +    config.unsupported = True
> +
> Index: test/Transforms/LoopIdiom/R600/popcnt.ll
> ===================================================================
> --- /dev/null
> +++ test/Transforms/LoopIdiom/R600/popcnt.ll
> @@ -0,0 +1,104 @@
> +; RUN: opt -loop-idiom -mtriple=r600-- -mcpu=SI -S < %s | FileCheck %s
> +
> +; Mostly copied from x86 version.
> +
> +;To recognize this pattern:
> +;int popcount(unsigned long long a) {
> +;    int c = 0;
> +;    while (a) {
> +;        c++;
> +;        a &= a - 1;
> +;    }
> +;    return c;
> +;}
> +;
> +
> +; CHECK-LABEL: @popcount_i64
> +; CHECK: entry
> +; CHECK: llvm.ctpop.i64
> +; CHECK: ret
> +define i32 @popcount_i64(i64 %a) nounwind uwtable readnone ssp {
> +entry:
> +  %tobool3 = icmp eq i64 %a, 0
> +  br i1 %tobool3, label %while.end, label %while.body
> +
> +while.body:                                       ; preds = %entry, %while.body
> +  %c.05 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
> +  %a.addr.04 = phi i64 [ %and, %while.body ], [ %a, %entry ]
> +  %inc = add nsw i32 %c.05, 1
> +  %sub = add i64 %a.addr.04, -1
> +  %and = and i64 %sub, %a.addr.04
> +  %tobool = icmp eq i64 %and, 0
> +  br i1 %tobool, label %while.end, label %while.body
> +
> +while.end:                                        ; preds = %while.body, %entry
> +  %c.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.body ]
> +  ret i32 %c.0.lcssa
> +}
> +
> +; CHECK-LABEL: @popcount_i32
> +; CHECK: entry
> +; CHECK: llvm.ctpop.i32
> +; CHECK: ret
> +define i32 @popcount_i32(i32 %a) nounwind uwtable readnone ssp {
> +entry:
> +  %tobool3 = icmp eq i32 %a, 0
> +  br i1 %tobool3, label %while.end, label %while.body
> +
> +while.body:                                       ; preds = %entry, %while.body
> +  %c.05 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
> +  %a.addr.04 = phi i32 [ %and, %while.body ], [ %a, %entry ]
> +  %inc = add nsw i32 %c.05, 1
> +  %sub = add i32 %a.addr.04, -1
> +  %and = and i32 %sub, %a.addr.04
> +  %tobool = icmp eq i32 %and, 0
> +  br i1 %tobool, label %while.end, label %while.body
> +
> +while.end:                                        ; preds = %while.body, %entry
> +  %c.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.body ]
> +  ret i32 %c.0.lcssa
> +}
> +
> +; To recognize this pattern:
> +;int popcount(unsigned long long a, int mydata1, int mydata2) {
> +;    int c = 0;
> +;    while (a) {
> +;        c++;
> +;        a &= a - 1;
> +;        mydata1 *= c;
> +;        mydata2 *= (int)a;
> +;    }
> +;    return c + mydata1 + mydata2;
> +;}
> +
> +; CHECK-LABEL: @popcount2
> +; CHECK: entry
> +; CHECK: llvm.ctpop.i64
> +; CHECK: ret
> +define i32 @popcount2(i64 %a, i32 %mydata1, i32 %mydata2) nounwind uwtable readnone ssp {
> +entry:
> +  %tobool9 = icmp eq i64 %a, 0
> +  br i1 %tobool9, label %while.end, label %while.body
> +
> +while.body:                                       ; preds = %entry, %while.body
> +  %c.013 = phi i32 [ %inc, %while.body ], [ 0, %entry ]
> +  %mydata2.addr.012 = phi i32 [ %mul1, %while.body ], [ %mydata2, %entry ]
> +  %mydata1.addr.011 = phi i32 [ %mul, %while.body ], [ %mydata1, %entry ]
> +  %a.addr.010 = phi i64 [ %and, %while.body ], [ %a, %entry ]
> +  %inc = add nsw i32 %c.013, 1
> +  %sub = add i64 %a.addr.010, -1
> +  %and = and i64 %sub, %a.addr.010
> +  %mul = mul nsw i32 %inc, %mydata1.addr.011
> +  %conv = trunc i64 %and to i32
> +  %mul1 = mul nsw i32 %conv, %mydata2.addr.012
> +  %tobool = icmp eq i64 %and, 0
> +  br i1 %tobool, label %while.end, label %while.body
> +
> +while.end:                                        ; preds = %while.body, %entry
> +  %c.0.lcssa = phi i32 [ 0, %entry ], [ %inc, %while.body ]
> +  %mydata2.addr.0.lcssa = phi i32 [ %mydata2, %entry ], [ %mul1, %while.body ]
> +  %mydata1.addr.0.lcssa = phi i32 [ %mydata1, %entry ], [ %mul, %while.body ]
> +  %add = add i32 %mydata2.addr.0.lcssa, %mydata1.addr.0.lcssa
> +  %add2 = add i32 %add, %c.0.lcssa
> +  ret i32 %add2
> +}

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