radeon/llvm: Declare the interpolation intrinsics as ReadOnly

This signals to the Dead Code Elimination pass that it is safe to
remove these instructions when they are dead.

2 files changed, 2 insertions, 1 deletions

diff --git a/src/gallium/drivers/radeon/SIInstrInfo.td b/src/gallium/drivers/radeon/SIInstrInfo.td
index 81df55d135e..55882808659 100644
--- a/src/gallium/drivers/radeon/SIInstrInfo.td
+++ b/src/gallium/drivers/radeon/SIInstrInfo.td
@@ -364,6 +364,7 @@ class VINTRP <bits <2> op, dag outs, dag ins, string asm, list<dag> pattern> :
   let EncodingType = 11; // SIInstrEncodingType::VINTRP
 
   let Uses = [M0];
+  let neverHasSideEffects = 1;
 }
 
 class VOP1 <bits<8> op, dag outs, dag ins, string asm, list<dag> pattern> :
diff --git a/src/gallium/drivers/radeon/SIIntrinsics.td b/src/gallium/drivers/radeon/SIIntrinsics.td
index b9544f10687..401325bf5b1 100644
--- a/src/gallium/drivers/radeon/SIIntrinsics.td
+++ b/src/gallium/drivers/radeon/SIIntrinsics.td
@@ -26,7 +26,7 @@ let TargetPrefix = "SI", isTarget = 1 in {
   /* Interpolation Intrinsics */
 
   def int_SI_set_M0 : Intrinsic <[llvm_i32_ty], [llvm_i32_ty]>;
-  class Interp : Intrinsic <[llvm_float_ty], [llvm_i32_ty, llvm_i32_ty, llvm_i32_ty], []>;
+  class Interp : Intrinsic <[llvm_float_ty], [llvm_i32_ty, llvm_i32_ty, llvm_i32_ty], [IntrReadMem]>;
 
   def int_SI_fs_interp_linear_center : Interp;
   def int_SI_fs_interp_linear_centroid : Interp;