[PATCH] D70595: [TargetLowering] Allow constants with multiple uses

[David Stuttard via Phabricator via llvm-commits]

dstuttard created this revision.
Herald added subscribers: llvm-commits, hiraditya, nhaehnle, jvesely.
Herald added a project: LLVM.

Multiple uses of a constant was causing an assert in target lowering for
propagating fnegs. Allow multiple uses when it is a constant fixes the issue.

Change-Id: Iffd1ce18bf13ec68d91ff47aecd7cf1918fd3c0a


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D70595

Files:
  llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
  llvm/test/CodeGen/AMDGPU/const-multiuse-tl.ll


Index: llvm/test/CodeGen/AMDGPU/const-multiuse-tl.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/const-multiuse-tl.ll
@@ -0,0 +1,54 @@
+; ModuleID = 'foo-new.bc'
+source_filename = "foo.ll"
+
+define amdgpu_ps void @main(float addrspace(6)* %arg1) #0 {
+main_body:
+  %tmp2 = load float, float addrspace(6)* %arg1
+  %tmp3 = call nsz float @llvm.floor.f32(float undef) #2
+  %tmp4 = fptosi float %tmp3 to i32
+  %tmp5 = add i32 0, %tmp4
+  %tmp6 = sub i32 0, %tmp5
+  %tmp7 = sitofp i32 %tmp4 to float
+  %tmp8 = fmul nsz float %tmp7, 0x3FEBB67AE0000000
+  %tmp9 = sitofp i32 %tmp6 to float
+  %tmp10 = call nsz float @llvm.fmuladd.f32(float %tmp9, float 0xBFEBB67AE0000000, float %tmp8) #2
+  %tmp11 = fsub nsz float 0.000000e+00, %tmp10
+  %tmp12 = call nsz float @llvm.fmuladd.f32(float %tmp11, float 5.000000e-01, float 5.000000e-01) #2
+  %tmp13 = call nsz float @llvm.fmuladd.f32(float 0.000000e+00, float %tmp2, float 5.000000e-01) #2
+  %tmp14 = call nsz float @llvm.floor.f32(float %tmp13) #2
+  %tmp15 = fptosi float %tmp14 to i32
+  %tmp16 = icmp eq i32 %tmp15, 0
+  br i1 %tmp16, label %endif06, label %if04
+
+if04:                                             ; preds = %main_body
+  %tmp17 = fadd nsz float %tmp12, -5.000000e-01
+  %tmp18 = fneg nsz float %tmp17
+  %tmp19 = fmul nsz float 0.000000e+00, %tmp18
+  %tmp20 = call nsz float @llvm.fmuladd.f32(float 0.000000e+00, float 0.000000e+00, float %tmp19) #2
+  %tmp21 = fadd nsz float %tmp20, 5.000000e-01
+  %tmp22 = fadd nsz float %tmp21, 0.000000e+00
+  %tmp23 = fmul nsz float %tmp22, 0.000000e+00
+  %tmp24 = call nsz <4 x float> @llvm.amdgcn.image.sample.2d.v4f32.f32(i32 15, float %tmp23, float undef, <8 x i32> undef, <4 x i32> undef, i1 false, i32 0, i32 0) #4
+  %tmp25 = extractelement <4 x float> %tmp24, i32 3
+  %tmp26 = fsub nsz float 1.000000e+00, %tmp25
+  %tmp27 = call nsz float @llvm.fmuladd.f32(float undef, float %tmp26, float undef) #2
+  unreachable
+
+endif06:                                          ; preds = %main_body
+  ret void
+}
+
+; Function Attrs: nounwind readonly
+declare <4 x float> @llvm.amdgcn.image.sample.2d.v4f32.f32(i32 immarg, float, float, <8 x i32>, <4 x i32>, i1 immarg, i32 immarg, i32 immarg) #1
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare float @llvm.floor.f32(float) #3
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare float @llvm.fmuladd.f32(float, float, float) #3
+
+attributes #0 = { "no-signed-zeros-fp-math"="true" }
+attributes #1 = { nounwind readonly }
+attributes #2 = { nounwind readnone }
+attributes #3 = { nounwind readnone speculatable willreturn }
+attributes #4 = { convergent nounwind readnone }
Index: llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -5385,8 +5385,10 @@
   EVT VT = Op.getValueType();
   const SDNodeFlags Flags = Op->getFlags();
   const TargetOptions &Options = DAG.getTarget().Options;
-  if (!Op.hasOneUse() && !(Op.getOpcode() == ISD::FP_EXTEND &&
-                           isFPExtFree(VT, Op.getOperand(0).getValueType())))
+  if (!Op.hasOneUse() &&
+      !(Op.getOpcode() == ISD::FP_EXTEND &&
+        isFPExtFree(VT, Op.getOperand(0).getValueType())) &&
+      !(Op.getOpcode() == ISD::ConstantFP))
     return 0;
 
   // Don't recurse exponentially.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D70595.230630.patch
Type: text/x-patch
Size: 3516 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20191122/5db9a1f9/attachment.bin>