[llvm] 1fa858d - [RISCV][GISel] Make G_CONSTANT of pointers legal.

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2023-08-14T10:11:29-07:00
New Revision: 1fa858d987ec0ffcc25005012d35eed25fa4c7d1

URL: https://github.com/llvm/llvm-project/commit/1fa858d987ec0ffcc25005012d35eed25fa4c7d1
DIFF: https://github.com/llvm/llvm-project/commit/1fa858d987ec0ffcc25005012d35eed25fa4c7d1.diff

LOG: [RISCV][GISel] Make G_CONSTANT of pointers legal.

This is needed to support things like null pointers.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D157822

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
    llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv32/legalize-const.mir
    llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-const.mir

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp b/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
index b6c212e068f03e..84077a67d156e4 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
@@ -22,6 +22,7 @@ using namespace llvm;
 RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST) {
   const unsigned XLen = ST.getXLen();
   const LLT XLenLLT = LLT::scalar(XLen);
+  const LLT p0 = LLT::pointer(0, XLen);
 
   using namespace TargetOpcode;
 
@@ -81,7 +82,7 @@ RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST) {
   }
 
   getActionDefinitionsBuilder({G_CONSTANT, G_IMPLICIT_DEF})
-      .legalFor({XLenLLT})
+      .legalFor({XLenLLT, p0})
       .widenScalarToNextPow2(0)
       .clampScalar(0, XLenLLT, XLenLLT);
 

diff  --git a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv32/legalize-const.mir b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv32/legalize-const.mir
index 817e3ff9175250..e2903b2296ef82 100644
--- a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv32/legalize-const.mir
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv32/legalize-const.mir
@@ -111,3 +111,16 @@ body:             |
     PseudoRET implicit $x10, implicit $x11, implicit $x12
 
 ...
+---
+name:            const_null
+body:             |
+  bb.0.entry:
+    ; CHECK-LABEL: name: const_null
+    ; CHECK: [[C:%[0-9]+]]:_(p0) = G_CONSTANT i32 0
+    ; CHECK-NEXT: $x10 = COPY [[C]](p0)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:_(p0) = G_CONSTANT i32 0
+    $x10 = COPY %0(p0)
+    PseudoRET implicit $x10
+
+...

diff  --git a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-const.mir b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-const.mir
index e2e3d9df1fac23..e2665b6657ce0e 100644
--- a/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-const.mir
+++ b/llvm/test/CodeGen/RISCV/GlobalISel/legalizer/rv64/legalize-const.mir
@@ -125,3 +125,16 @@ body:             |
     PseudoRET implicit $x10, implicit $x11, implicit $x12
 
 ...
+---
+name:            const_null
+body:             |
+  bb.0.entry:
+    ; CHECK-LABEL: name: const_null
+    ; CHECK: [[C:%[0-9]+]]:_(p0) = G_CONSTANT i64 0
+    ; CHECK-NEXT: $x10 = COPY [[C]](p0)
+    ; CHECK-NEXT: PseudoRET implicit $x10
+    %0:_(p0) = G_CONSTANT i64 0
+    $x10 = COPY %0(p0)
+    PseudoRET implicit $x10
+
+...