Value soft float calls as more expensive in the inliner.

Summary: When evaluating floating point instructions in the inliner, ask the TTI whether it is an expensive operation.  By default, it's not an expensive operation.  This keeps the default behavior the same as before.  The ARM TTI has been updated to return back TCC_Expensive for targets which don't have hardware floating point.

Reviewers: chandlerc, echristo

Reviewed By: echristo

Subscribers: t.p.northover, aemerson, llvm-commits

Differential Revision: http://reviews.llvm.org/D6936

llvm-svn: 228263

1 files changed, 136 insertions, 0 deletions

diff --git a/llvm/test/Transforms/Inline/inline-fp.ll b/llvm/test/Transforms/Inline/inline-fp.ll
new file mode 100644
index 00000000000..4d18ce87a5a
--- /dev/null
+++ b/llvm/test/Transforms/Inline/inline-fp.ll
@@ -0,0 +1,136 @@
+; RUN: opt -S -inline < %s | FileCheck %s
+; Make sure that soft float implementations are calculated as being more expensive
+; to the inliner.
+
+define i32 @test_nofp() #0 {
+; f_nofp() has the "use-soft-float" attribute, so it should never get inlined.
+; CHECK-LABEL: test_nofp
+; CHECK: call float @f_nofp 
+entry:
+  %responseX = alloca i32, align 4
+  %responseY = alloca i32, align 4
+  %responseZ = alloca i32, align 4
+  %valueX = alloca i8, align 1
+  %valueY = alloca i8, align 1
+  %valueZ = alloca i8, align 1
+
+  call void @getX(i32* %responseX, i8* %valueX)
+  call void @getY(i32* %responseY, i8* %valueY)
+  call void @getZ(i32* %responseZ, i8* %valueZ)
+
+  %0 = load i32* %responseX
+  %1 = load i8* %valueX
+  %call = call float @f_nofp(i32 %0, i8 zeroext %1)
+  %2 = load i32* %responseZ
+  %3 = load i8* %valueZ
+  %call2 = call float @f_nofp(i32 %2, i8 zeroext %3)
+  %call3 = call float @fabsf(float %call)
+  %cmp = fcmp ogt float %call3, 0x3FC1EB8520000000
+  br i1 %cmp, label %if.end12, label %if.else
+
+if.else:                                          ; preds = %entry
+  %4 = load i32* %responseY
+  %5 = load i8* %valueY
+  %call1 = call float @f_nofp(i32 %4, i8 zeroext %5)
+  %call4 = call float @fabsf(float %call1)
+  %cmp5 = fcmp ogt float %call4, 0x3FC1EB8520000000
+  br i1 %cmp5, label %if.end12, label %if.else7
+
+if.else7:                                         ; preds = %if.else
+  %call8 = call float @fabsf(float %call2)
+  %cmp9 = fcmp ogt float %call8, 0x3FC1EB8520000000
+  br i1 %cmp9, label %if.then10, label %if.end12
+
+if.then10:                                        ; preds = %if.else7
+  br label %if.end12
+
+if.end12:                                         ; preds = %if.else, %entry, %if.then10, %if.else7
+  %success.0 = phi i32 [ 0, %if.then10 ], [ 1, %if.else7 ], [ 0, %entry ], [ 0, %if.else ]
+  ret i32 %success.0
+}
+
+define i32 @test_hasfp() #0 {
+; f_hasfp()  does not have the "use-soft-float" attribute, so it should get inlined.
+; CHECK-LABEL: test_hasfp
+; CHECK-NOT: call float @f_hasfp 
+entry:
+  %responseX = alloca i32, align 4
+  %responseY = alloca i32, align 4
+  %responseZ = alloca i32, align 4
+  %valueX = alloca i8, align 1
+  %valueY = alloca i8, align 1
+  %valueZ = alloca i8, align 1
+
+  call void @getX(i32* %responseX, i8* %valueX)
+  call void @getY(i32* %responseY, i8* %valueY)
+  call void @getZ(i32* %responseZ, i8* %valueZ)
+
+  %0 = load i32* %responseX
+  %1 = load i8* %valueX
+  %call = call float @f_hasfp(i32 %0, i8 zeroext %1)
+  %2 = load i32* %responseZ
+  %3 = load i8* %valueZ
+  %call2 = call float @f_hasfp(i32 %2, i8 zeroext %3)
+  %call3 = call float @fabsf(float %call)
+  %cmp = fcmp ogt float %call3, 0x3FC1EB8520000000
+  br i1 %cmp, label %if.end12, label %if.else
+
+if.else:                                          ; preds = %entry
+  %4 = load i32* %responseY
+  %5 = load i8* %valueY
+  %call1 = call float @f_hasfp(i32 %4, i8 zeroext %5)
+  %call4 = call float @fabsf(float %call1)
+  %cmp5 = fcmp ogt float %call4, 0x3FC1EB8520000000
+  br i1 %cmp5, label %if.end12, label %if.else7
+
+if.else7:                                         ; preds = %if.else
+  %call8 = call float @fabsf(float %call2)
+  %cmp9 = fcmp ogt float %call8, 0x3FC1EB8520000000
+  br i1 %cmp9, label %if.then10, label %if.end12
+
+if.then10:                                        ; preds = %if.else7
+  br label %if.end12
+
+if.end12:                                         ; preds = %if.else, %entry, %if.then10, %if.else7
+  %success.0 = phi i32 [ 0, %if.then10 ], [ 1, %if.else7 ], [ 0, %entry ], [ 0, %if.else ]
+  ret i32 %success.0
+}
+
+declare void @getX(i32*, i8*) #0
+
+declare void @getY(i32*, i8*) #0
+
+declare void @getZ(i32*, i8*) #0
+
+define internal float @f_hasfp(i32 %response, i8 zeroext %value1) #0 {
+entry:
+  %conv = zext i8 %value1 to i32
+  %sub = add nsw i32 %conv, -1
+  %conv1 = sitofp i32 %sub to float
+  %0 = tail call float @llvm.pow.f32(float 0x3FF028F5C0000000, float %conv1)
+  %mul = fmul float %0, 2.620000e+03
+  %conv2 = sitofp i32 %response to float
+  %sub3 = fsub float %conv2, %mul
+  %div = fdiv float %sub3, %mul
+  ret float %div
+}
+
+define internal float @f_nofp(i32 %response, i8 zeroext %value1) #1 {
+entry:
+  %conv = zext i8 %value1 to i32
+  %sub = add nsw i32 %conv, -1
+  %conv1 = sitofp i32 %sub to float
+  %0 = tail call float @llvm.pow.f32(float 0x3FF028F5C0000000, float %conv1)
+  %mul = fmul float %0, 2.620000e+03
+  %conv2 = sitofp i32 %response to float
+  %sub3 = fsub float %conv2, %mul
+  %div = fdiv float %sub3, %mul
+  ret float %div
+}
+
+declare float @fabsf(float) optsize minsize
+
+declare float @llvm.pow.f32(float, float) optsize minsize
+
+attributes #0 = { minsize optsize }
+attributes #1 = { minsize optsize "use-soft-float"="true" }